![Introduction to Arrays
Arrays are a type of data structure that stores a set of a particular data, which has been
placed in contagious memory location. Arrays should be looked at more than just a set of
data, but a set of variables of the same data type. Each piece of data stored in array is
known as an element and his its own unique identifier. Regardless on the length or type of
array that is used the first element is always a 0. Take a look below at the below example.
In the above example, we have 5 blocks which can store 5 sets of data of the same type.
When we declare an array, we declare it like a variable as we have to give a data type and
a name, but we also have to declare how many elements we expect our array to hold. We
do this by using square brackets [] with a number inside. Based on the example above our
arrays has 5 elements [5]. Below is an example of how a simple array is declared in C++:
int numbers[5];
Like variables arrays can either be initialised with predefined values when they are
declared. To initialise an array with a set of values, we need to use a set {} to store that
data. Based on the examples we have used so far, this is how you would initialise an array:
int numbers[5] = {11, 22, 33, 44, 55};
As we have initialised all elements of our array, this is how our array would look like
based on the first example above:
You may find yourself in situation, where you only need to initialise a few elements of the
array, for example you may initialise the array like below:
int numbers[5] = {11, 22, 33};
By initialising the first 3 elements of the array, the other elements have been left undefined
and as a result, will default to the value of 0. See the below example.
Activity 33: My first array](https://image.slidesharecdn.com/anintroductiontocacompl-michaeloliver-150127021603-conversion-gate02/85/An-Introduction-to-C-A-complete-beginners-guide-Michael-Oliver-103-320.jpg)
![In this program we are going to create the exact array that we have been working with in
the example above, and we are going to print all our elements out to the screen. To print
out each element of the array, we need to cycle through it using a for loop. Create a new
project called “My First Array” copy the below code, save and compile.
#include <iostream>
using namespace std;
int main()
{
int numbers[5]{11, 22, 33, 44, 55};// array declared and initialised
for (int i = 0; i < 5; i++)//for loop created with correct loop iterations
{
//loop iterations i, will print the correct element of the array
cout << numbers[i] << endl;
}
return 0;
}
In this program the for loop is the key to the working of
the array. We have created a new variable calledint i which is used to help us locate which
element in the array needs to be printed, once the for loop completes its iteration the
counter then goes to the next element of the array.](https://image.slidesharecdn.com/anintroductiontocacompl-michaeloliver-150127021603-conversion-gate02/85/An-Introduction-to-C-A-complete-beginners-guide-Michael-Oliver-104-320.jpg)
![Activity 34: Entering Data into an array at run time
In this activity we are going to declare a new integer array and initialise the value of the
array at runtime. Create a new project called “Array Input”, enter the code below, save and
compile.
#include <iostream>
using namespace std;
int main()
{
int numbers[5];
int i;//int i declared here so both loops can access the data stored
cout << “Please enter 5 numbers: “;
for (i = 0; i < 5; i++)//for loop created to get input
{
cin >> numbers[i];
}
cout << “The numbers you entered are: “;
for (i = 0; i < 5; i++)//for loop created to display output
{
cout<< numbers[i]<<” “;
}
cout<< endl;
return 0;
}
Have you noticed that in this program that the
variable “i” we used for the loops, was declared outside of the for loop? This is because](https://image.slidesharecdn.com/anintroductiontocacompl-michaeloliver-150127021603-conversion-gate02/85/An-Introduction-to-C-A-complete-beginners-guide-Michael-Oliver-105-320.jpg)
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X
X
Uppercase X
89
131
59
01011001
Y
Y
Uppercase Y
90
132
5A
01011010
Z
Z
Uppercase Z
91
133
5B
01011011
[
[
Opening bracket
92
134
5C
01011100
\
Backslash
93
135
5D
01011101
]
]
Closing bracket
94
136
5E
01011110
^
^
Caret - circumflex
95
137
5F
01011111
_
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Underscore
96
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`
`
Grave accent
97
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a
a
Lowercase a
98
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b
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An Introduction to C++ A complete beginners guide - Michael Oliver
- 6. Introduction to C++ C++ was developed by Bjarne Stroustrup of AT&T Bell Laboratories in the early 1980’s, and is based on the C language. The name is a pun - “++” is a syntactic construct used in C (to increment a variable), and C++ is intended as an incremental improvement of C. Most of C is a subset of C++, so that most C programs can be compiled (i.e. converted into a series of low-level instructions that the computer can execute directly) using a C++ compiler. C++ is considered to be a multi paradigm language, as the way it can be implemented can vary. This book will cover C++ as a procedural language, and conforms to the ANSI (American national standard institute) and ISO (International standards organisations). This means that you can take all the source code from this book, and run it in any compiler. To be able to successfully run the source code in this book you will need the following: A computer (Windows, OSx, Linux) An IDE (Integrated development environment) Windows (Visual Studio) OSx (X code) Linux (Code Blocks) For a free version of this software, then please visit www.bcotcomputing.co.uk All source code in this guide has been implemented using Visual Studio 2013 professional and can be found on the school’s website. This software has been installed on all of the machines in the school of computer of science. It can also be downloaded for free using your dreams spark account by clicking this link
- 8. Creating your first C++ project in Visual studio 2013 This guide has been created to show how to setup, create and compile your first C++ program “Hello world”. Before you begin to code your program, you will need to load up an IDE (Integrated development environment) To do this click the start icon , and type visual. You should see the following: Click “Visual Studio 2013” and the Visual Studio loading screen will appear on your desktop: After the loading screen, the Visual Studio start page should load. In this screen you can create new projects, open existing projects or even access guidance and resources. To create a new project we need to click “new project”. Once you click on new project, you will be presented with a new window (See below) in the left hand pane you will a series of programming languages. By default visual C++ will
- 10. Once you have named the project, click next and you will be presented with a win32 Application wizard. To proceed click next. On this screen you need to ensure the radio button called “console application” is checked and the checkbox “empty project” is also checked. Once this has been completed, click finish. If you fail to do this part correctly you will have to start your project again. Your wizard will have closed, and you will have been brought to the main screen which shows you, your project files. At the moment, we haven’t got any active C++ files. So you will need to create one before we can begin coding.
- 12. You will come to a new window that will require you to choose the file type needed as part of your project. Choose visual C++ in the left hand pane (Default) and then select “C++ file”. Then click open, which will create a new file and open in your project. Your nearly there, your file has now been created, but we need to save it to the right location otherwise any code placed inside your file will not work. To move the file to the correct location, click file, and at the bottom of the menu will be an option called “Move source1.cpp into”, move your mouse over this option and a new menu, will appear called “1 Hello World”. Select this option to move your C++ file into the correct location.
- 17. Understanding your 1st C++ Program Now that you have successfully created your first C++ program called“Hello World”, let’s look at the structure of your program, and break down the code bit by bit. Letslook at the“Hello World” program below. //My first C++ program #include <iostream> using namespace std; int main() { cout<<“Hello World” <<endl; return 0; } //My first C++ program This is a single comment line which has not affect on the performance of a program. We use comments to annotate our code, to explain what the program does. There are two ways to display comments (//) is used for a single line. To write a description of a particular program or source code, you may wish to go over several lines of code. To do this we use (/* */) #include <iostream> In programming we use a directive that tells the compiler (Visual studio) how it should process its input. Directives can vary from compiler to compiler and behave differently and are processed by a pre-processor. A pre-processor is a program that processes its input data, to produce an output. Different languages use different pre-processor, but in C languages, the most common is pre-processor, takes lines starting with # as directives. The above #include <iostream> tells the pre-processor of the compiler to include the iostream standard file. This file includes the fundamental delectations of the input-output library in C++. Without this your C++ would not compile. using namespace std; All the elements of the standard C++ library are declared within what is called a namespace, the namespace with the name std. So in order to access its functionality we
- 18. declare with this expression that we will be using these entities. This line is very frequent in C++ programs that use the standard library. int main() This line corresponds to the beginning of the definition of the main function. The main function is the point by where all C++ programs start their execution, independently of its location within the source code. It does not matter whether there are other functions with other names defined before or after it - the instructions contained within this function’s definition will always be the first ones to be executed in any C++ program. For that same reason, it is essential that all C++ programs have a main function. The word main is followed in the code by a pair of parentheses (()). That is because it is a function declaration: In C++, what differentiates a function declaration from other types of expressions are these parentheses that follow its name. Optionally, these parentheses may enclose a list of parameters within them. Right after these parentheses we can find the body of the main function enclosed in braces ({}). What is contained within these braces is what the function does when it is executed. cout<<“Hello World” <<endl; This line is a C++ statement. A statement is a simple or compound expression that can actually produce some effect. In fact, this statement performs the only action that generates a visible effect in our first program. cout is the name of the standard output stream in C++, and the meaning of the entire statement is to insert a sequence of characters (in this case the Hello World sequence of characters) into the standard output stream (cout, which usually corresponds to the screen). cout is declared in the iostream standard file within the std namespace, so that’s why we needed to include that specific file and to declare that we were going to use this specific namespace earlier in our code. Notice that the statement ends with a semicolon character (;). This character is used to mark the end of the statement and in fact it must be included at the end of all expression statements in all C++ programs (one of the most common syntax errors is indeed to forget to include some semicolon after a statement). <<endl; is used after the output statement to move any other statements onto its own separate line of the output window. As seem above in the output window “Press any key to continue” is on its own separate line. If the <<endl; was removed then the output statement “hello world” would be on the same line as “press any key to continue”. return 0; The return statement causes the main function to finish. Return may be followed by a return code (in our example is followed by the return code with a value of zero). A return code of 0 for the main function is generally interpreted as the program worked as expected without any errors during its execution. This is the most usual way to end a C++ console
- 19. program.
- 21. Solving Errors in C++ When you begin coding in C++, you will notice that you may make several errors in your code, such as missing the semi-colon (;) or using uppercase letters when in fact you should be using lower case. The best way to become familiar with any language is to practice rectifying errors in the code. Activity 2: Solving errors Below is a C++ program, which has 7 errors. Create a new project and copy the code below into your new project and resolve the issues. HINT: use the code from your first program to help. Once you have finished, save and compile your program. #include <Iostream> using namespace std; int Main() { Cout <“Please Fix my Errors “ << endl Return 0; }; To view your errors in C++, you can use the built in error tool, which tells you where the errors have occurred within your program. To access this tool, click view on the top toolbar and select error list. Double click on each error in this list to be taken to the line of code where the error has occurred.
- 23. Annotating Your Code When you code in any programming language, it’s extremely important that you use comments to explain what is happening. This is so that other programmers, can understand your code and what your program is trying to achieve. Activity 3: Annotating your code Below is a C++ program that shows you how to use comments. Create a new project called “comments” and copy the below program, save and compile the code. #include <iostream> using namespace std; int main() { // This is how you add a comment on to a single line /*This is how to add a comment over multiple lines. The compiler will not read this. Comments are used to annotate your code*/ cout << “Hello World” ; return 0; } It will be expected that as you progress through the work book, that you will be required to annotate all of your programs.
- 26. Adding Multiple Line of Code Now that you have coded your first simple C++ program, let’s look at making it a bit more complex, by adding more lines of code. Activity 4: Adding Multiple lines of code Create a new C++ project called“multiple lines”, and using the code below, copy the code into your program, then save and compile your program. #include <iostream> using namespace std; int main() { cout<<“This is line 3” <<endl; //endl is used to place the code on a new line cout<<“This is line 5n”; // n is another way of putting the code onto a new line return 0; } You will have noticed that you have used (/n) and (<<endl) to print the code on to a new line. As you continue to learn C++ you will choose a method that is suited to your programming style. There is no wrong or right way, just the way that suits you. This book will use <<endl throughout, but you can change this to suit your needs.
- 28. Introduction to Variables Variables are temporary storage that exist as long as they need to, then are disposed of. Imagine a calculator, the numbers you input are stored in the calculator until you use the clear button or turn the calculator off, then the values are gone. Variables are stored in the main memory of a computer system, and given a unique address so that they can be accessed by the compiler at any time. Variables are declared by the type of data to be expected, such as number, a letter or a sentence. Declaring the data type is essential to ensure that the correct machine code is generated by the compiler to be used by the CPU (Central processing Unit). What Data types can a variable hold? Integers (int) An int is short for an integer which is a whole number such as 0,1,2,3,4,5,6,7,8,9 etc. They can be both signed (negative) and unsigned (positive). Integers can range in size depending on the type of integer that is being used. Characters (char) A char which is short of character is a data type that can hold single letter, symbol or number such as ‘A’, ‘b’, ‘@‘, ‘$’, ‘1’ etc. A simple char will use at least 1 byte (8 bits) of storage space. Float (Decimal) A float, which is short for floating point number is a way of storing a number, which has a decimal place such as 3.2, 6.8, 7.1 etc. Depending on the type of float used will depend on their precision. There are two types of floating point numbers which are Floats and doubles. Doubles have a greater precision and generally the preferable data type to be used within a C++ program. Strings Strings are very powerful and used to not only store words, but are used to store a combination of words and numbers. Strings are useful when you want to capture information such as the full name of the person (First name and surname) street address etc. Boolean Boolean in C++ is known as bool, which is represented in either two states; true or false. You may see that this data type is used with binary numbers, this again reflects the two states of Boolean. 0= false and 1 = true.
- 30. Declaring Variables in C++ To declare a variable in C++, we need to declare the type of data that we expect the variable to hold, this can be done by typing the data type name in, as shown below in the table: Data type’s: How to declare Integer int Float double Character char string string Float float Boolean bool When you type the data type in C++, you will notice that the text will change colour, this is to show that it will be used by the compiler for a variable assignment. Once you have chosen the data type for your variable, you will need to assign it a name. You can name the variable anything you like, as long as you follow the rules: Variable Name Rules When variables are created, you give them a name such as num1, housename, fname, etc. Variables are very flexible with names, however there are some golden rules to creating them: A Variable name consists of any combination of alphabets, digits and underscores. Some compiler allows variable names whole length could be up to 247 characters. Still it would be safer to stick to the rule of 31 characters. Please avoid creating long variable name as it adds to your typing effort. All variable names must begin with a letter of the alphabet or an underscore( _ ). For beginning programmers, it may be easier to begin all variable names with a letter of the alphabet. The first character must not be a number or any special symbol After the first initial letter, variable names can also contain letters and numbers. No spaces or special characters, however, are allowed. Uppercase characters are distinct from lowercase characters. Using all uppercase letters is used primarily to identify constant variables. You cannot use a C++ keyword (reserved word) as a variable name. Examples of variables being assigned int num1; //num1 is the variable name I have chosen which expects an intger data type. float num2; // num2 is the variable name chosen which expects a float data type.
- 36. Using floats in C++ We are now going to look at Floats in C++ and see how they can be implemented. Floats are used to show numbers after the decimal place. Depending on the type of float used, will depend on the precision (how many numbers are after the decimal point). For example using the float in C++ can show up to 7 places after the decimal point, where a double can show up to 16. The two programs demonstrate this. Activity 6 Create a new C++ program called “My Float” and copy the code below, compile and run. #include <iostream> using namespace std; int main() { float number1 = 3.123456789; double number2 = 3.123456789; cout << number1 << endl; cout << number2 << endl; return 0; } Further reading and on floating point numbers can be found here Activity 7 – Using Multiple variables
- 38. Using strings Strings are used when you need to store data that contains more than one character such as a name, email address, or postcode. Strings are different to all other data types in C++, as you have to call a new programming library. Activity 8 – Using Strings In this program you are going to create your first C++ program that displays “Hello world” in a string variable. Create a new C++ program called “intro to strings”, enter the code below and compile the program. #include <iostream> #include <string>//the new string header has to be used or string will not work. using namespace std; int main() { string hello =“Hello World”; cout << “Please enter your first name: “ << endl; cout << hello << ” Welcome to C++”<<endl; return 0; } If you wanted to store a combination of words and letters into the same variable, rather than using a string, you could use a Char Array. Arrays are covered towards the end of this guide and is the start of intermediate C++. Another program below has been included to show how two separate strings can be concatenated together to form one string. #include <iostream> #include <string> using namespace std; int main() {
- 41. Getting User Input There will be times where you will need to get the user to input some form of data in to your program, that you can use either use for conditional statements and loops or if your write certain instructions out onto the screen. To gather input we need to use the “cin>>” command followed by the name of the variable that will be holding the data. For example cin>>name; Activity 7 – User input (Integer) In this program you are going to create a C++ program that allows a user to input a number and display that number back out on the screen. Create a new C++ project called “intger input” and enter the below code, compile and run. #include <iostream> using namespace std; int main() { int num; cout << “Please enter a number”; cin>>num; cout<< “You entered “ <<num <<endl; return 0; } Activity 8 – User input (String) In the below program you will create a program that will allow a user to enter a name (without spaces) and display it back out to the user. Enter the code below, save, compile and run. #include <iostream> #include <string>//the new string header has to be used or string will not work. using namespace std; int main() { string name;
- 43. Now that you know how to declare variables, allow user data input and display the results back out to the user it’s time to create your own C++ program that captures user information. Your program will need to capture the following data: First name, Surname, Age, House number, 1st line of address, City State Postcode You can use previous exercises to help you design this program. In this program you will expected to do the following: Use comments to explain your code Indent your code correctly Use the correct variable type and appropriate variable names As an extension to this exercise concatenate the two string variables used to hold the first and second name into one string, so that it can be printed out on one line.
- 46. int main() { int num1, num2, sum; cout << “Please enter your first number to add: “; cin >> num1; cout << “Please enter your second number to add: “; cin >> num2; sum = num1*num2; //times variable num 1 and 2, and store new number in variable sum cout << num1 << “x” << num2 << “=” << sum; return 0; } Activity 11– Peas in a Pod Create a new project called “Peas and Pods” and enter the below code. Enter the following program, making sure that intentional errors introduced are corrected. The case of all letters must be copied as shown. Save, compile and run the program. #include <iostream> using namespace std; int main() { int number_of_pods; int peas_per_pod; int total_peas; cout << “Enter the number of pods:n”; cin >> number_of_pods; cout << “Enter the number of peas in a pod:n”; cin >> peas_per_pod; total_peas = number_of_pods * peas_per_pod; cout << “If you have “;
- 47. cout << number_of_pods; cout << ” pea podsn”; cout << “and “; cout << peas_per_pod; cout << ” peas in each pod, thenn”; cout << “you have “; cout << total_peas; cout << ” peas in all the pods.n”; return 0; } Now that you have successfully compiled the above program, you will need to try and shorten the program, by reducing the lines of code. Based on previous examples shown in the guide so far, shorten the code above onto a fewer lines as possible.
- 49. Global and local variables We know how to use variables, but so far you have bene using local variables. Local variables are variables that are declared within side a function, and are made only available to that function. The other type of variable is a Global Variable, which is declared outside a function and is made available to all functions in a C++ program. Global variables are useful, but the value they hold can easily be manipulated by the different functions that use them. Many developers avoid using global variables and instead pass data from one function to another to avoid the data being lost. Activity 12 – Global and Local Variables In this program, we are going to declare one global variable, and two local variables. One of these variables will be a standard local variable and the other will be declared as a constant. A constant is a variable that must have a value initialised before the program runs, and its value will remain the same throughout the program. Constants can’t have their value changed at run time. #include <iostream> using namespace std; int num1; //I am a global variable, I can be used by any function within C++ int main() { const int num2=5; // I am a constant local variable. I can be used within this function only and my value will never change. int num3; //I am a local variable and can only be used within the “main” function cout<<“Please enter a number for global variable num1: “; cin>>num1; cout<<“We are going to add “<<num1 <<“to our constant variable, which has the value of 5”<<endl; cout<<num1 << ” + “ <<num2 << ” = “ <<(num3=num1+num2) <<endl; return 0; }
- 51. Intro conditional statements Conditional Statements: A condition statement in C++ is when we check to see if a certain condition has been met. Condition statements are great, when you want to display different results depending on what the user selects. In programming a condition is also known as if/else statements. In this exercise you will cover if/else statements. They are also a great way to change the direction depending on what the user selects. In programming a condition is also known as if/else statements. In this exercise you will cover if/else statements. Conditional statements can have multiple conditions, which are tested in order. An example of an conditional statement is: If Joshua eats all his dinner, then he can go out and play. If not then he must go tidy his room. Depending on the result of Joshua eating his dinner with depend on the outcome. IF Joshua = Eat All dinner Then go out and play This is condition 1 Else IF Joshua = doesn’t eat his dinner Then Tidy your room This is condition 2 In this section of C++ you will be introduced to new symbols that you will need to familiarise yourself with. The table below explains these symbols. == Equal too && and != Not Equal too || Or > Greater Than >= More than and equal too < Less than <= Less than and equal too
- 53. Activity 13: In this activity we are creating a simple if statement where a user is prompted to enter a number between under 10. This program has two outcomes/condition, depending on the number that the user enters will depend on what condition becomes true. Create a new C++ project and call it “condition statements”. Enter the below code, save and compile the program. #include <iostream> using namespace std; int main () { int num; cout<<“Please enter a number under 10 : “; cin>>num; if (num <=10) //outcome 1 cout<<“Your number was 10 or less”; else //outcome 2 cout<<“Your number was greater than 10”; return 0; } Well done you have just created your first C++ program that uses a condition statements. In the next exercise you will learn how to code a C++ with more than two outcomes, which can develop a solution if the user enters a number of 10. Create a C++ program that uses a conditional statement for a teacher who wants to know what action should be taken for a student who has not completed their homework. The program will need to be called “Teacher Program” and have two conditions:
- 58. Logical Operators and Conditional statements The logical operators && and || are used when evaluating two expressions to obtain a single relational result. The operator && corresponds with Boolean logical operation AND. This operation results true if both its two operands are true and false otherwise. The following panel shows the result of operator && evaluating the expression a && b: && (AND) OPERATOR a b a && b true true true The && operator is used if you want to check if multiple conditions have been met. For example. If Joshua eats his dinner (A) and does his homework(B) he can go out and play. Unless both A and B are true, then the statement is false true false False false true False false false False The operator || corresponds with Boolean logical operation OR. This operation results true if either one of its two operands is true, thus being false only when both operands are false themselves. Here are the possible results of a || b: || (OR) OPERATOR a b a || b true true true The || operator is used to check if any condition has been met, despite the other statements. For example. If Joshua eats his dinner (A) or does his homework (B) then he can go out and play. If A or B is true then, then the statement is true. true false True false true True false false False The Operator ! is the C++ operator to perform the Boolean operation NOT, it has only one operand, located at its right, and the only thing that it does is to inverse the value of it, producing false if its operand is true and true if its operand is false. Basically, it returns the opposite Boolean value of evaluating its operand. For example: !(5 == 5) // evaluates to false because the expression at its right (5 == 5) is true. !(6 <= 4) // evaluates to true because (6 <= 4) would be false. !true // evaluates to false !false // evaluates to true.
- 64. Activity 17: Using Not Operators In this activity we use the ! (NOT) operator so you can see how we can test for a condition that is not true. #include <iostream> using namespace std; int main() { int num1; cout<<“Please enter any number, other than 5: “; cin>>num1; if (num1 != 5)// if number is NOT 5 { cout<<“Well don your number was not 5”<<endl; } else // if number is 5 { cout<<“Your number was 5”<<endl; } return 0; } You have created a series of program that uses a variety of conditional statements. Now it’s time to take what you have learnt and put it into practice! Design and build the following program: You need to create a grading programing where the lecturer can put in a grade percentage and the program will state what grade the student got. The outputs could be something like this
- 67. Creating a calculator using conditional statements Activity 18- Creating a calculator In this C++ you code a simple calculator to perform any calculation, copy the below code into a new project called “Calculator”, save and compile. #include <iostream> using namespace std; int main() { float a, b, c; char m; cout<<“Do you want to add(+), subtract(-), multiply(x), or divide(/)?:” ; cin>>m; cout<<“Enter a number: “ ; cin>>a; cout<<“Enter a second number: “ ; cin>>b; cout<<“The answer is: “; if (m == ‘+’) { cout<<(c = a + b) <<endl; } else if (m == ‘-‘) { cout<<(c = a - b) <<endl; } else if (m == ‘x’) { cout<<(c = a * b) <<endl;
- 75. Try re-entering the values ‘A’ and ‘a’ in again. Did you notice that you got the same result? Well done you have compared the value you have entered against the case of your program. Activity 22: Creating a menu using switch statements In this activity you will use integers to create a simple menu for a café. Create a new program called “Café Menu” and enter the below code, save and compile. #include <iostream> using namespace std; int main () { int choice; cout<<“Option 1: Eat Breakfast”<<endl; cout<<“Option 2: Wash up the dishes”<<endl; cout<<“Option 3: Make a drink”<<endl; cout<<“What would you like to eat? Please enter a number to make your choice “; cin>>choice; switch (choice) { case 1: cout<<“Bacon Bap”<<endl; break;
- 76. case 2: cout<<“Sausage roll”<<endl; break; case 3: cout<<“Bowl of porridge “<<endl; break; default: cout<<“invalid choice”<<endl; break; } return 0; } So you now have used case statements for both chars and integers, but something was missing from both programs that can improve the readability of both programs, did you know what? To improve the readability and prevent the chances of something going wrong we should use parentheses {} for each case. So each case should look like this: case 1: { //code here break; } Go back through both of your programs that use switch statements and place the parentheses in, ensure that you compile and test each program to ensure that they work.
- 78. Nesting switch/case statements Nesting switches it’s exactly the same as nesting if/else statements it’s a switch inside a switch. Activity 23 – Nesting switch statements In this program you will create a C++ program that has a nested switch for a cinema system. Create a new program called nesting switch, copy the code, save and compile. #include <iostream> using namespace std; int main () { int choice, film; cout<<“1. View Prices”<<endl; cout<<“2. View Times “<<endl; cout<<“3. View Films”<<endl; cin>>choice; switch(choice) { case 1: { cout<<“You have chossen to view prices”; cout<<“Student: £5.59”; cout<<“Adult: £7.00”; cout<<“Concession: £5.40”; break; } case 2: { cout<<“what film would you like to watch? ” <<endl; cout<<“1. The Hobbit: The Battle of Five Armies “<<endl; cout<<“2. The Imitation Game”<<endl; cout<<“3. Frozen”<<endl; cin>>film; switch(film) { case 1: {
- 80. break; } case 3: { cout<<“The Hobbit: The Battle of five armies”<<endl; cout<<“The Imitation Game”<<endl; cout<<“Frozen”<<endl; break; } default: { cout<<“You have entered an invalid menu choice”<<endl; cout<<“Please try again”<<endl; break; } } return 0; } Important! Nesting switches can get confusing and most of the errors you will encounter will be because you haven’t closed your case using parentheses {}. Please ensure that you check that you close all your cases. You will have noticed the above program with the nested switch does not contain the times for each film, only the days. You will need to create another nested statement for each for film. This means that your program will contain 3 nested switches.
- 85. While loops The while loop is the simplest kind of loop that you can use in C++. The while loop will repeat the statement whilst the condition is true. When the loop is executed, if the condition was to change to false, then the loop will no longer run. Activity 24 – While loops (decrement counter) Create a C++ program, called “Lift off” and copy the below code, save and compile. #include <iostream> using namespace std; int main () { int num = 10; while (num>0) //repeat while num is less than 0 { cout << num << “, “; —num; //decremental counter. Every time the loop repeats num-1. } cout << “liftoff!n”; return 0; } Activity 25 – While loop (Increment counter) Create a C++ program called “counting” and copy the below code, save and compile. #include <iostream> using namespace std; int main () { int num = 0;
- 88. cout<<num<<endl; system(“pause”); int num = 0; }while (!done); return 0; } In activity 23, you were asked to code a C++ program which had nested switch statements. Using the same code for that program, wrap the entire code in a do while loop, to allow the user to repeat the program again without exiting out of it. Activity 26 - Fix the errors Below is a C++ program that has several errors in, using what you have learnt create a new C++ project called “Errors with Loops”, copy the below code and fix the errors. Save and compile to ensure all errors have been resolved. #include <iostream> using namespace std; main() { int num1, num2; char again; do cout << “Enter a number: “; cin >> num1; cout << “Enter another number: “; cin >> num2; cout << “Their sum is “ << (num1 + num2) << endl; cout << “Do you want to do this again? “; cin >> again; while (again == ‘y’ || again ++ ‘Y’); return 0; }
- 94. For Loops A for loop is a special type of loop that will loop a specific amount of types, unlike a while and do while which will only loop if a condition is true. For loops are particularly useful when dealing with data structures like arrays, which will be covered later in this guide. Activity 28 In this program, we are going to count how many loop iterations have taken place. A loop iteration is known as how many times a loop is executed. Create a new C++ program called “for loops” enter the below code, save and compile. #include <iostream> using namespace std; int main() { int i; for (i=1; i<11; i++) { cout<<“loop iteration: “ <<i<<endl; } return 0; } How many iterations did you get? If coded correctly you would have gotten 10. If you change the number 11 in the above program to another number you will get (n-1) of iterations. Give it a try and see what you get. Activity 29 In this activity we have changed the rules of the for loop to count down from 10 rather than count up. Compare the conditions and the counter from the previous program. Create a new C++ project called “count down”, copy the code, save and compile.
- 98. Introduction to Functions Functions are dedicated blocks of code that perform a specific task. They are used to break code into smaller chunks making the program easier to understand. Functions promote reusability and are useful for saving space in the program. The activities below show the different types of functions, and how they are used within the C++ environment. Activity 31 In this program, we care going to create a simple function that uses the type void. Void should only be used when a function does not return any value. For example a function that only prints out statements (like the one below) will only need to use the void type. Create a new program called “My first function”, copy the below code, compile and run. #include <iostream> using namespace std; void banner()//code function here { cout << “I am a simple function”<<endl; } int main() { banner();//call function here return 0; }
- 100. Activity 32 In this program, we are using functions to pass data between each other. This method is in replacement of Global variables, and is the best practice for allowing specific functions to access certain data, without compromising its integrity. The program below, has a function called “add” that is responsible for adding two values together and returning the sum of these two values to the “main” function, which is then printed out to the screen. Create a program called “Function Addition”, copy the code below and compile. #include <iostream> using namespace std; int add(int num1, int num2)//code function here with parameters { int sum = num1 + num2; // return sum; //value of sum is the number that is returned to main } int main() { int result = add(2, 3); //pass the values of 2 and 3 to the add function cout << “The result is “ << result <<endl; // } Understanding what the program is doing line by line. This program has two functions, one called “add”, and the other called “main”. These functions have both been declared as type integers, as they are both dealing with numbers. int add(int num1, int num2) In this line, we are creating a function called “add” that is of type integer, which has two parameters. A parameter is a variable that expects data to be passed to it from another function, these are known as arguments. This function has two parameters both of type integer called num1 and num2. int sum = num1 + num2; A local variable called sum, has been created to add the values of num1 and num2 together. This is something you should be comfortable with by now, as you have used this type of declaration in previous C++ activities. return sum;
- 103. Introduction to Arrays Arrays are a type of data structure that stores a set of a particular data, which has been placed in contagious memory location. Arrays should be looked at more than just a set of data, but a set of variables of the same data type. Each piece of data stored in array is known as an element and his its own unique identifier. Regardless on the length or type of array that is used the first element is always a 0. Take a look below at the below example. In the above example, we have 5 blocks which can store 5 sets of data of the same type. When we declare an array, we declare it like a variable as we have to give a data type and a name, but we also have to declare how many elements we expect our array to hold. We do this by using square brackets [] with a number inside. Based on the example above our arrays has 5 elements [5]. Below is an example of how a simple array is declared in C++: int numbers[5]; Like variables arrays can either be initialised with predefined values when they are declared. To initialise an array with a set of values, we need to use a set {} to store that data. Based on the examples we have used so far, this is how you would initialise an array: int numbers[5] = {11, 22, 33, 44, 55}; As we have initialised all elements of our array, this is how our array would look like based on the first example above: You may find yourself in situation, where you only need to initialise a few elements of the array, for example you may initialise the array like below: int numbers[5] = {11, 22, 33}; By initialising the first 3 elements of the array, the other elements have been left undefined and as a result, will default to the value of 0. See the below example. Activity 33: My first array
- 104. In this program we are going to create the exact array that we have been working with in the example above, and we are going to print all our elements out to the screen. To print out each element of the array, we need to cycle through it using a for loop. Create a new project called “My First Array” copy the below code, save and compile. #include <iostream> using namespace std; int main() { int numbers[5]{11, 22, 33, 44, 55};// array declared and initialised for (int i = 0; i < 5; i++)//for loop created with correct loop iterations { //loop iterations i, will print the correct element of the array cout << numbers[i] << endl; } return 0; } In this program the for loop is the key to the working of the array. We have created a new variable calledint i which is used to help us locate which element in the array needs to be printed, once the for loop completes its iteration the counter then goes to the next element of the array.
- 105. Activity 34: Entering Data into an array at run time In this activity we are going to declare a new integer array and initialise the value of the array at runtime. Create a new project called “Array Input”, enter the code below, save and compile. #include <iostream> using namespace std; int main() { int numbers[5]; int i;//int i declared here so both loops can access the data stored cout << “Please enter 5 numbers: “; for (i = 0; i < 5; i++)//for loop created to get input { cin >> numbers[i]; } cout << “The numbers you entered are: “; for (i = 0; i < 5; i++)//for loop created to display output { cout<< numbers[i]<<” “; } cout<< endl; return 0; } Have you noticed that in this program that the variable “i” we used for the loops, was declared outside of the for loop? This is because
- 108. Extension Activities Below is a series of extension activates, with given scenarios. Create a separate program for each scenario. Extension Activity 1 The RentCo Car Rental Company rents cars for £35 per day plus 10 pence per mile. Write a program for the rental company so that the user can enter the date that the car was rented, the number of days it was rented for, the mileage when the car was rented, and the mileage when the car was returned. Calculate the total charges and display the results. Extension Activity 2 A simple address book system holds names, addresses and telephone numbers for friends and family. The system stores: Surname and first name Two lines of the address and a post code Telephone number Date of birth Email address Write a program to allow the user to input these details and then display them on screen. Extension Activity 3 Temperatures can be converted from Fahrenheit to Centigrade. Research the formula required to convert a temperature from Fahrenheit to Centigrade. Write a program to input a Fahrenheit temperature and output the equivalent temperature in Centigrade. Extension Activity 4 Write a program to work out your pocket money spending by carrying out the following steps: Input a variable pocketmoney to the amount of money you get each month. Output the title ‘Pocket Money’ Output the number of pounds at the start of the month Input the number of pounds spent on food Input the number of pounds spent on your mobile phone
- 111. The ASCII Table Computers can only understand one language, which is binary. Computers can’t understand characters such as ‘@’ or ‘y’, they can only understand their binary equivalent. The ASCII (American standard code of information interchange) table shows the numerical representation of a character in decimal, which is then converted to binary by the compilers interpreter. Character codes 0 – 31 of the ASCII table are non-printing characters. Character codes 32-127 are printable characters and character’s Character codes 128-255 are the extended ASCII codes for printable characters. The ASCII table is extremely important as it helps us understand that no two values are the same. See the below example: The character ‘A’ and ‘a’ to humans have the same meaning (obviously one is a capital letter). But to a computer system they are completely different with two different meanings. ‘A’ has the value of 65 which in binary is: 01000001 ‘a’ has the value of 97 which in binary is: 01011101 It’s important that we understand that these values are different and the CPU handles these values in a different way.
- 113. ASCII Table (Binary values 31-127) Below is the ASCII table for values 31-127. The table shows the decimal, octal, hexadecimal and HTML value of each character within the above range. DEC OCT HEX BIN Symbol HTML Number HTML Name Description 32 040 20 00100000   Space 33 041 21 00100001 ! ! Exclamation mark 34 042 22 00100010 ” " " Double quotes (or speech marks) 35 043 23 00100011 # # Number 36 044 24 00100100 $ $ Dollar 37 045 25 00100101 % % Procenttecken 38 046 26 00100110 & & & Ampersand 39 047 27 00100111 ’ ' Single quote 40 050 28 00101000 ( ( Open parenthesis (or open bracket) 41 051 29 00101001 ) ) Close parenthesis (or close bracket) 42 052 2A 00101010 * * Asterisk 43 053 2B 00101011 + + Plus
- 116. 72 110 48 01001000 H H Uppercase H 73 111 49 01001001 I I Uppercase I 74 112 4A 01001010 J J Uppercase J 75 113 4B 01001011 K K Uppercase K 76 114 4C 01001100 L L Uppercase L 77 115 4D 01001101 M M Uppercase M 78 116 4E 01001110 N N Uppercase N 79 117 4F 01001111 O O Uppercase O 80 120 50 01010000 P P Uppercase P 81 121 51 01010001 Q Q Uppercase Q 82 122 52 01010010 R R Uppercase R 83 123 53 01010011 S S Uppercase S 84 124 54 01010100 T T Uppercase T 85 125 55 01010101 U U Uppercase U 86 126 56 01010110 V V Uppercase V
- 117. 87 127 57 01010111 W W Uppercase W 88 130 58 01011000 X X Uppercase X 89 131 59 01011001 Y Y Uppercase Y 90 132 5A 01011010 Z Z Uppercase Z 91 133 5B 01011011 [ [ Opening bracket 92 134 5C 01011100 \ Backslash 93 135 5D 01011101 ] ] Closing bracket 94 136 5E 01011110 ^ ^ Caret - circumflex 95 137 5F 01011111 _ _ Underscore 96 140 60 01100000 ` ` Grave accent 97 141 61 01100001 a a Lowercase a 98 142 62 01100010 b b Lowercase b 99 143 63 01100011 c c Lowercase c 100 144 64 01100100 d d Lowercase d 101 145 65 01100101 e e Lowercase e