![Hierarchy of operators
Operator Description Associativity
( ), [ ] Function call, array
element reference
Left to Right
+, -, ++, - -
,!,~,*,&
Unary plus, minus,
increment, decrement,
logical negation, 1’s
complement, pointer
reference, address
Right to Left
*, / , % Multiplication,
division, modulus
Left to Right](https://image.slidesharecdn.com/chap2-160308123432/85/Variables-Data-Types-Operator-Expression-in-c-in-detail-39-320.jpg)
![Order of evaluation
3/8/2016
42
Highest () [] ->
! ~ ++ -- (type *) & sizeof
* / %
+ -
<< >>
< <= > >=
== !=
&
^
|
&&
||
? :
= += -= *= /=
Lowest ,](https://image.slidesharecdn.com/chap2-160308123432/85/Variables-Data-Types-Operator-Expression-in-c-in-detail-42-320.jpg)
Variables, Data Types, Operator & Expression in c in detail
- 1. VARIABLES, DATA TYPES, OPERATOR & EXPRESSION Chap 23/8/2016 1
- 2. Contents 2.1 Character Set 2.2 C Tokens Keywords & Identifiers Constants Integer, Floating Point, Character, String, Enumeration 2.3 Backslash characters / Escape sequences 2.4 Data Types in C 2.5 Variables 2.6 Declaration & Definition 2.7 User-Defined Type declarations 2.8 Operators & Expressions Arithmetic, Relational, Logical, Increment Decrement , Bit wise, Assignment, Conditional 2.9 Type conversions in Expressions 2.10 Implicit Type Conversion 2.11 Explicit Type Conversions 2.12 Precedence & Associability of Operators. 3/8/2016 2
- 3. 2.1 character set in c 3 3/8/2016
- 4. 2.1 character set in c 3/8/2016 4
- 5. 2.2 C tokens 3/8/2016 5 Smallest individual units is called as ‘Tokens ‘
- 6. Keywords And Identifiers 3/8/2016 6 Every C word is classified either “Keyword” or “Identifier “. Rules for Keywords Has fixed meaning Meaning can not be changed Served as basic building block for program statement. Must be written in lower case
- 8. Keywords and Identifiers 3/8/2016 8 Identifiers Refer to names of variables , functions and arrays Rules for identifiers 1. First character must be an alphabet (or underscore) 2. Must consist of only letters, digits or underscore. 3. Only first 31 characters are significant. 4. Cannot use a keyword 5. Must not contain white space
- 9. Constants 3/8/2016 9 Constants Numeric Constants Integer Constants Real Constants Character constants Single Character Constants String Constants Constants in C refers to fixed values and do not change during the execution of a program
- 10. constants 3/8/2016 10 Integer Constants Real Constants can be represented as exponential format. mantissa e exponent Mantissa is either a real number expressed in decimal notation or integer The exponent is an integer number with an optional plus or minus sign The letter e can be written in lowercase or uppercase.
- 11. constants 11 Single character constants String constants Backslash Character constants – useful in output functions also known as escape sequences 3/8/2016
- 13. Variables 3/8/2016 13 A data name used to store data values May take different values at different times of program execution Rules for variable 1. Should not be keyword 2. Should not contain white space 3. Uppercase and lower case are significant 4. Must begin with letter ( or underscore) 5. Normally should not be more than eight characters.
- 14. Data Transformation Programs transform data from one form to another Input data Output data Stimulus Response Programming languages store and process data in various ways depending on the type of the data; consequently, all data read, processed, or written by a program must have a type Two distinguishing characteristics of a programming language are the data types it supports and the operations on those data types
- 15. 2.4 Data types 3/8/2016 15 C is rich in its data type. Variety of data type allows programmer to select appropriate data type as per need ANSI supports 3 classes of data type 1. Primary or fundamental data type 2. Derived data type 3. User defined data type.
- 16. Data types in C 3/8/2016 16
- 17. Data types in C 3/8/2016 17
- 18. 3/8/2016 18
- 20. Expressions Combination of Operators and Operands Example 2 * y + 5 Operands Operators
- 21. Definition “An operator is a symbol (+,-,*,/) that directs the computer to perform certain mathematical or logical manipulations and is usually used to manipulate data and variables” Ex: a+b
- 22. Operators in C 1. Arithmetic operators 2. Relational operators 3. Logical operators 4. Assignment operators 5. Increment and decrement operators 6. Conditional operators 7. Bitwise operators 8. Special operators
- 23. Arithmetic operators Operator example Meaning + a + b Addition –unary - a – b Subtraction- unary * a * b Multiplication / a / b Division % a % b Modulo division- remainder
- 24. Relational Operators Operator Meaning < Is less than <= Is less than or equal to > Is greater than >= Is greater than or equal to == Equal to != Not equal to
- 25. Logical Operators Operator Meaning && Logical AND || Logical OR ! Logical NOT Logical expression or a compound relational expression- An expression that combines two or more relational expressions Ex: if (a==b && b==c)
- 26. Truth Table a b Value of the expression a && b a || b 0 0 0 0 0 1 0 1 1 0 0 1 1 1 1 1
- 27. Assignment operators Syntax: v op = exp; Where v = variable, op = shorthand assignment operator exp = expression Ex: x=x+3 x+=3
- 28. Shorthand Assignment operators Simple assignment operator Shorthand operator a = a+1 a + =1 a = a-1 a - =1 a = a* (m+n) a * = m+n a = a / (m+n) a / = m+n a = a %b a %=b
- 29. Increment & Decrement Operators C supports 2 useful operators namely 1. Increment ++ 2. Decrement – operators The ++ operator adds a value 1 to the operand The – operator subtracts 1 from the operand ++a or a++ --a or a--
- 30. Rules for ++ & -- operators 1. These require variables as their operands 2. When postfix either ++ or – is used with the variable in a given expression, the expression is evaluated first and then it is incremented or decremented by one 3. When prefix either ++ or – is used with the variable in a given expression, it is incremented or decremented by one first and then the expression is evaluated with the new value
- 31. Examples for ++ & -- operators Let the value of a =5 and b=++a then a = b =6 Let the value of a = 5 and b=a++ then a =5 but b=6 i.e.: 1. a prefix operator first adds 1 to the operand and then the result is assigned to the variable on the left 2. a postfix operator first assigns the value to the variable on left and then increments the operand.
- 32. Conditional operators Syntax: exp1 ? exp2 : exp3 Where exp1,exp2 and exp3 are expressions Working of the ? Operator: Exp1 is evaluated first, if it is nonzero(1/true) then the expression2 is evaluated and this becomes the value of the expression, If exp1 is false(0/zero) exp3 is evaluated and its value becomes the value of the expression Ex: m=2; n=3 r=(m>n) ? m : n;
- 33. Bitwise operators These operators allow manipulation of data at the bit level Operator Meaning & Bitwise AND | Bitwise OR ^ Bitwise exclusive OR << Shift left >> Shift right
- 34. Special operators 1. Comma operator ( ,) 2. sizeof operator – sizeof( ) 3. Pointer operators – ( & and *) 4. Member selection operators – ( . and ->)
- 35. Arithmetic Expressions Algebraic expression C expression axb-c a*b-c (m+n)(x+y) (m+n)*(x+y) a*b/c 3x2+2x+1 3*x*x+2*x+1 a/b S=(a+b+c)/2 c ab b a 2 cba S=
- 36. Arithmetic Expressions Algebraic expression C expression area= area=sqrt(s*(s-a)*(s-b)*(s-c)) sin(b/sqrt(a*a+b*b)) tow1=sqrt((rowx-rowy)/2+tow*x*y*y) tow1=sqrt(pow((rowx-rowy)/2,2)+tow*x*y*y) y=(alpha+beta)/sin(theta*3.1416/180)+abs(x) ))()(( csbsass Sin 22 ba b 2 1 2 xy yx 2 2 1 2 xy yx xy sin
- 37. Precedence of operators BODMAS RULE- Brackets of Division Multiplication Addition Subtraction Brackets will have the highest precedence and have to be evaluated first, then comes of , then comes division, multiplication, addition and finally subtraction. C language uses some rules in evaluating the expressions and they r called as precedence rules or sometimes also referred to as hierarchy of operations, with some operators with highest precedence and some with least. The 2 distinct priority levels of arithmetic operators in c are- Highest priority : * / % Lowest priority : + -
- 38. Rules for evaluation of expression 1. First parenthesized sub expression from left to right are evaluated. 2. If parentheses are nested, the evaluation begins with the innermost sub expression 3. The precedence rule is applied in determining the order of application of operators in evaluating sub expressions 4. The associatively rule is applied when 2 or more operators of the same precedence level appear in a sub expression. 5. Arithmetic expressions are evaluated from left to right using the rules of precedence 6. When parentheses are used, the expressions within parentheses assume highest priority
- 39. Hierarchy of operators Operator Description Associativity ( ), [ ] Function call, array element reference Left to Right +, -, ++, - - ,!,~,*,& Unary plus, minus, increment, decrement, logical negation, 1’s complement, pointer reference, address Right to Left *, / , % Multiplication, division, modulus Left to Right
- 40. Example 1 Evaluate x1=(-b+ sqrt (b*b-4*a*c))/(2*a) @ a=1, b=-5, c=6 =(-(-5)+sqrt((-5)(-5)-4*1*6))/(2*1) =(5 + sqrt((-5)(-5)-4*1*6))/(2*1) =(5 + sqrt(25 -4*1*6))/(2*1) =(5 + sqrt(25 -4*6))/(2*1) =(5 + sqrt(25 -24))/(2*1) =(5 + sqrt(1))/(2*1) =(5 + 1.0)/(2*1) =(6.0)/(2*1) =6.0/2 = 3.0
- 41. Example 2 Evaluate the expression when a=4 b=a- ++a =a – 5 =5-5 =0
- 42. Order of evaluation 3/8/2016 42 Highest () [] -> ! ~ ++ -- (type *) & sizeof * / % + - << >> < <= > >= == != & ^ | && || ? : = += -= *= /= Lowest ,
- 43. 43 2.9 Type conversions in expressions 1. Implicit Type Conversion C permits mixing of constants and variables of different types in an expression. C automatically converts any intermediate values to the proper type so that the expression can be evaluated without loosing any significance. This automatic conversion is known as implicit type conversion. The rule of type conversion: the lower type is automatically converted to the higher type.
- 44. 44 2.14 Type conversions in expressions for example, int i, x; float f; double d; long int li ; The final result of an expression is converted to the type of the variable on the left of the assignment. long long float float float float double doubleint x = li / i + i * f – d
- 45. 45 3.14 Type conversions in expressions Conversion Hierarchy is given below long int Conversion hierarchy charshort float double long double int unsigned long int
- 46. 46 3.14 Type conversions in expressions 2. Explicit conversion We can force a type conversion in a way . The general form of explicit conversion is ( type-name ) expression for example x = ( int ) 7.5 ; a = ( int ) 21.3 / (int) 4.5; a = ( float ) 3 / 2 ; a = float ( 3 / 2 ) ;
- 47. 47 2.15 Operator precedence and Associativity Rules of Precedence and Associativity (1)Precedence rules decides the order in which different operators are applied. (2)Associativity rule decide the order in which multiple occurrences of the same level operator are applied. Table3.8 on page71 shows the summary of C Operators. for example, a = i +1== j || k and 3 != x