c programming Operators
Operators are ‘C’ tokens which can join together individual constants, variables array elements, and function references. Operators act upon data items called as operands.
Classification
- Arithmetic operators
- Relational operators
- Logical operators
- Assignment operator
- Increment and decrement operator
- Conditional operator
- Bitwise operator
- Special operator
Arithmetic Operators
| Arithmetic operator | Meaning |
| + | Adding or unary plus |
| – | Subtraction or unary minus |
| * | Multiplication |
| / | Division |
| % | Modulo division |
- For arithmetic operations, operands must be numeric values.
- Here modulo division produces reminder of integer division.
- arithmetic operations are classified as
- Integer arithmetic
- Real arithmetic
- Mixed mode arithmetic
Integer arithmetic: Both the operands are an integer in integer arithmetic. It always yields an integer value.
Ex: int a=10,b=5; a+b; a-b; a*b; a/b ; a%b etc.
Real arithmetic: Both the operands are real in real arithmetic. It yields real values as a result. It cannot be applied to the % operator.
Ex:
float a=10.0, b=5.0; a+b=10.0+5.0=15.0 i.e. 15.000000 a-b= 10.0-5.0 =5.0 i.e. 5.000000 a*b= 10.0*5.0 =50.0 i.e. 50.000000 a/b= 10.0/5.0 = 2.0 i.e. 2.000000 a%b=10.0%5.0 (invalid expression)
Mixed Mode Arithmetic: when one operand is an integer and other is real it is known as mixed mode arithmetic. Here the result will always be real.
Ex:
int a=10; float b=5.0; a+b=10+5.0=15.0 a-b = 10-5.0 =5.0 a*b = 10*5.0 =50.0 a/b = 10/5.0 = 2.0 a%b=10%5.0 (invalid expression)
Relational Operators
These are used to compare two quantities. These operators always return 1(true) or 0 (false). If the expression is true then it returns with 1 else 0
| Relational Operator | Action |
| < | is less than |
| <= | is less than or equal to |
| > | is greater than |
| >= | is greater than or equal to |
| == | is equal to |
| != | is not equal to |
| Expression | Result |
| 10<5 | 0 (false) |
| 10>5 | 1 (true) |
| 10==15 | 0 (false) |
| 10!=15 | 1 (true) |
| (10+5)==(3*5) | 1 (true) |
Logical Operators
| logical Operator | Action |
| && | logical AND |
| || | logical OR |
| ! | logical NOT |
- Logical expression combines two or more relational expressions.
- Logical operators are used to testing more than one condition and make a decision.
- Logical AND: The result of logical AND expression will be true only when both the relational expression is true.
Syntax:exp1 && exp2;
- Logical OR: The result of logical OR expression will be false only when both relational expressions are false.
Syntax: exp1 || exp2;
- Logical NOT: The result of the expression will be true if the expression is false and vice versa
.Syntax:!exp1;
Ex:
int a=10,b=15, c=20,i; i= (a>b) && (b<c); //The value of i in this expression will be 0. i= (a<b) && (b<c); //The value of i in this expression will be 1. i= (a>b) || (b<c); //The value of i in this expression will be 1. i= ! (a>b); //The value of i in this expression will be 1.
Assignment Operators
The operators are used to assign the result of an expression to a variable
Syntax: Variable = exp;
| Assignment Operator Ex: int a=10,b=5; | Action |
| a=a+1; or a+=1; | adds 1 to a and assigns the value to a |
| a=a-1; or a-=1; | decrements a by 1 and assigns the value to a |
| a=a/(b+1) or a/=b+1; | divides a by (b+1) and assigns the result in a |
| a*=b+2; or a=a*(b+2) | multiplies (b+2) with a and assigns the result in a |
Increment and Decrement operators
- These operators are represented as ‘++’ and ‘–’.
- ++ Increments operand by 1 and –- decrement the value by 1.
- These are the unary operators and takes the following forms,
| Operator (int a,b) | Action | Result |
| a=1; b=++a; | pre-increment | increments a value by 1 and assigns the value to b. i.e., a=2 and b=2 |
| a= 1; b=a++; | post-increment | Assigns the value to b then increments a value by 1. i.e., a=2 and b=1 |
| a=2; b=–a; | pre-decrement | decrements a value by 1 and assigns the value to b. i.e., a=1 and b=1 |
| a=2; b=a–; | post-decrement | Assigns the value to b then decrements a value by 1. i.e., a=1 and b=2 |
Conditional Operator
- It is also known as a ternary operator
Syntax:exp1 ? exp2 : exp3;
Where exp1, exp2, and exp3 are expressions
Ex:
int a=5,b=10,c=15,y; y=(a>b) ? b : c; //The value of y is 15 y=(a<b) ? b : c; //The value of y is 10
Ex2:
/* Greatest of three numbers using conditional operation */ int a=5,b=10,c=15,y; y=(a>b && a>c) ? a: (b>c) ? b: c; //Here greatest of three numbers is stored in x;
Bitwise Operators
Bitwise operators are similar to that of logical operators except that they work on binary bits. When bitwise operators are used with variables, they are internally converted to binary numbers and then bitwise operators are applied on individual bits.
Bitwise operators do manipulation on bit stored in memory. These operators work with char and int type only. They cannot use floating point numbers.
| Bitwise Operators | Action |
| ~ | 1’s compliment |
| | | Bitwise OR |
| ^ | Bitwise exclusive OR |
| & | Bitwise AND |
| << | Left shift |
| >> | Right shift |
Ex:
int a=10,b=8; //Assum that int size is 2 bytes
/* The equivalent binary value of a is 0000 0000 0000 1010
The equivalent binary value of b is 0000 0000 0000 1000
*/
printf("%d", a & b); // The value of a & b = 0000 0000 0000 1000 i.e.,8
printf("%d", a|b); // The value of a | b = 0000 0000 0000 1010 i.e., 10
printf("%d", a^b); //The value of a ^ b= 0000 0000 0000 0010 i.e., 2
printf("%d" ,a<<2);
/*
a(10) binary is 0000 0000 0000 1010 a<<2.
It left shift the binary bits twice. i.e.,0000 0000 0010 1000 i.e. 40 */
printf("%d", a>>2);
/*
a(10) binary is 0000 0000 0000 1010 a>>2.
It right shifts the binary bits twice. i.e., 0000 0000 0000 0010 i.e. 2
*/
Special Operator
There are some special operators available in ‘C’ such as sizeof operator and member selection operators (. and →).
sizeof Operator: It returns numbers of bytes the operand occupies; operand may be a variable, a constant, or a data type qualifier.
Syntax: sizeof(operand)
Ex:
int y; y= sizeof (int); //here value of y will be 2 byte it its 16bit compiler
Member Operators: These are used to access members of structure and unions.
Operators priority wise
| Operators | Operation | Clubbing | Priority |
| ()
[] -> . |
Function call
Square bracket Structure operator Structure operator |
Left to Right | 1st |
| +
– ++ — ! ~ * & sizeof type |
Unary plus
Unary minus Increment Decrement Not operator Ones complement Pointer operator Address operator Size of an object Type case |
Right to Left | 2nd |
| *
/ % |
Multiplication
Division Modular division |
Left to Right | 3rd |
| +
_ |
Addition
Subtraction |
Left to Right | 4th |
| <<
>> |
Left shift
Right shift |
Left to Right | 5th |
| <
<= > >= |
Less than
Less than or equal to Greater than Greater than or equal to |
Left to Right | 6th |
| ==
!= |
Equality
Inequality |
Left to right | 7th |
| & | Bitwise AND | Left to right | 8th |
| ^ | Bitwise XOR | Left to right | 9th |
| | | Bitwise OR | Left to right | 10th |
| && | Logical AND | Left to right | 11th |
| || | Logical OR | Left to right | 12th |
| ? : | Conditional operator | Right to left | 13th |
| =, +=,-=,*=, /=, %=, &=,^=, |=, <<=, >>= | Assignment operators | Right to left | 14th |
Expressions
An expression in C is constructed using operators, variables and or constants.
Ex:
x+y*3.5 x<y x<y && x>5