![Basic Functions
A C program consists of one or more functions that contain a group of statements
which perform a specific task.
A C program must at least have one function: the function main.
We can create our own function or use the functions that has been declared in C
library (called Predefined function).
In order to use Predefined functions, we have to include the appropriate header file
(example: stdio.h).
[continue…]](https://image.slidesharecdn.com/basicsofc-copy-191024130003/85/Basics-of-c-Nisarg-Patel-14-320.jpg)
Basics of c Nisarg Patel
- 2. INTRODUCTION TO C PROGRAMMING C language : Is system programming language. Is procedure-oriented programming language. Is also called mid level programming language. was developed in 1972 by Dennis Ritchie at bell laboratories of AT&T(American Telephone & Telegraph), located in U.S.A. was developed to be used in UNIX Operating system.
- 3. FEATURES • Simple • Machine Independent or Portable • Mid-level programming language • structured programming language • Rich Library • Memory Management • Fast Speed • Pointers • Recursion • Extensible
- 4. Structure of a C program
- 5. FIRST PROGRAM OF LANGUAGE PROGRAM : #include <stdio.h> #include <conio.h> void main() { printf("Hello World"); getch(); } OUTPUT : Hello World
- 6. DESCRIBING THE PROGRAM #include <stdio.h> includes the standard input output library functions. The printf() function is defined in stdio.h #include <conio.h> includes the console input output library functions. The getch() function is defined in conio.h file void main() The main() function is the entry point of every program in C language. The void keyword specifies that it returns no value printf() The printf() function is used to print data on the console. getch() The getch() function asks for a single character. Until you press any key, it blocks the screen
- 7. INPUT OUTPUT FUNCTION Used to send data to the standard output (usually the monitor) to be printed according to specific format There are two input output function of c language. Printf(): printf() is used for output. It prints the given statement to the console. Syntax of printf() is given below: printf(“control string”,variables); Sample Format strings : %d(integer), %c(character), %s(string), %f(float) etc. Control string is a combination of text, format specifier and escape sequence.
- 8. scanf() Reads data from the standard input device (usually keyboard)and store it in a variable. The General format is: – scanf(“Control string”, &variable); The general format is pretty much the same as printf() except that it passes the address of the variable (notice the & sign) instead of the variable itself to the second function argument. Example: int age; printf(“Enter your age: “); scanf(“%d”, &age);
- 9. getchar() and putchar() getchar() - reads a character from standard input putchar() - writes a character to standard output • Example: #include <stdio.h> void main(void) { char my_char; printf(“Please type a character: “); my_char = getchar(); printf(“nYou have typed this character: “); putchar(my_char); }
- 10. Preprocessor Directives The first statement to be checked by the compiler • Preprocessor Directives always preceded with ‘#’ sign • They contain information to the compiler which are required by the compiler during compilation. • There are a few compiler directives. But only 2 of them will be discussed here. #include <stdio.h> • Tells the compiler to include the file stdio.h during compilation • Anything in the header file will be included a part of the program #define VALUE 10 • Tells the compiler to substitute the word VALUE with 10 during compilation
- 11. Comments Comment means explanations or annotations that are included in a program for documentation and clarification purpose. • Comments are completely ignored by the compiler during compilation and have no effect on program execution. • Comments starts with ‘/*’ and ends with ‘*/’ • Some compiler support comments starting with ‘//’
- 12. Variable A variable can be declared globally or locally. A globally declared variable can be accessed from any part of the program. A locally declared variable can only be accessed from inside the function in which the variable is declared.
- 13. Statements A specification of an action to be taken by the computer as the program executes is called a Statement. In the previous example, there are 2 lines following variable declaration that terminate with semicolon ‘;’ are statements: global_var = local_var + VALUE; printf (“Total sum is: %dn”, global_var); Each line is a statement that end with a semicolon is a statement.
- 14. Basic Functions A C program consists of one or more functions that contain a group of statements which perform a specific task. A C program must at least have one function: the function main. We can create our own function or use the functions that has been declared in C library (called Predefined function). In order to use Predefined functions, we have to include the appropriate header file (example: stdio.h). [continue…]
- 15. In this section, we will learn a few functions that are pre-defined in the header file stdio.h • These functions are: – printf() – scanf() – getchar() & putchar() • In addition to those functions, we will also learn about Format Specifier and Escape Sequence which are used with printf() and scanf().
- 16. DATA TYPES & KEYWORDS 4 types of data types A keyword is a reserved word. You cannot use it as a variable name, constant name etc.
- 17. Operators Arithmetic Operators Relational Operators Shift Operators Logical Operators Bitwise Operators Ternary or Conditional Operators Assignment Operator
- 18. CONTROL STATEMENTS • if-else If statement If-else statement If else-if ladder Nested if switch loops do-while loop while loop for loop break continue
- 19. IF-ELSE IN C