Operators

Operators are the symbol or sign which performs an operation in one or more operands. For example:  5+10 where, +is an operator to perform addition between 5 and 10 operands.
Operators can be classified as:

1) Arithmetic Operators: An operator that perform mathematical calculation of values or variables.

Arithmetic operator may be

Unary Operator	Binary Operator
It is used with one value or variable	It is used with two variables
Eg. -5, +a	Eg. a+b, 5-6
Unary operator are+ , -	Binary operator are+, -, *, /  and %

Operator	Meaning of Operator
+	addition or unary plus
-	subtraction or  unary minus
*	Multiplication
/	Division
%	remainder after division( modulo division)

Example of working of arithmetic operators

/* Program to demonstrate the working of arithmetic operators in C.*/

#include<stdio.h>

int main(){

int a=9,b=4,c;

    c=a+b;

printf("a+b=%d\n",c);

    c=a-b;

printf("a-b=%d\n",c);

    c=a*b;

printf("a*b=%d\n",c);

    c=a/b;

printf("a/b=%d\n",c);

    c=a%b;

printf("Remainder when a divided by b=%d\n",c);

return0;

}

}

output:

a+b=13

a-b=5

a*b=36

a/b=2

a%b=1

                                                                

2)Relational Operator: Relational operators checks relationship between two operands. If the relation is true, it returns value 1 and if the relation is false, it returns value 0. For example:

a>b

Here, > is a relational operator. If a is greater than b, a>b returns 1 if not then, it returns 0.

Relational operators are used in decision making and loops in C programming.

Operator	Meaning of Operator	Example
==	Equal to	5==3 returns false (0)
>	Greater than	5>3 returns true (1)
<	Less than	5<3 returns false (0)
!=	Not equal to	5!=3 returns true(1)
>=	Greater than or equal to	5>=3 returns true (1)
<=	Less than or equal to	5<=3 return false (0)

3)Logical Operators: Logical operators are used to combine expressions containing relation operators. In C, there are 3 logical operators:

Operator	Meaning of Operator	Example	Explanation
&&	Logical AND	((x>5) && (y<0))	Returns true if x greater than 5 and y less than 0.
||	Logical OR	((x>5)  || (y<0))	Returns true if x greater than 5 or y less than 0.
!	Logical NOT	X !=0	Returns true if x  is not equal to 0.

4)Bitewise Operators: A bitwise operator works on each bit of data. Bitwise operators are used in bit level programming.

Operators	Meaning of operators
&	Bitwise AND
|	Bitwise OR
^	Bitwise exclusive OR
~	Bitwise complement
<<	Shift left
>>	Shift right

5)Assignment Operators: The most common assignment operator is =. This operator assigns the value in right side to the left side. For example:

var=5  //5 is assigned to var

a=c;   //value of c is assigned to a

5=c;   // Error! 5 is a constant.

Operator	Shorthand	Assignment
+=	a+=b	a=a+b
-=	a-=b	a=a-b
*=	a*=b	a=a*b
/=	a/=b	a=a/b
%=	a%=b	a=a%b

6) Shorthand Operators: The mathematical operation (+, -, *, /, and %) merge with assignment operator (=) is called shorthand operators. The mathematical operators come before assignment operator at the expression.

7) Comma Operator: Comma operators are used to link expressions together. Comma operator is represented by “,”. This operator is used to evaluate left to right hand side. For example

x = (2, 4, 6,121);
The value of x becomes 121 by replacing all previous values of x.
8) Increment and Decrement Operators:In C, ++ and -- are called increment and decrement operators respectively. Both of these operators are unary operators, i.e, used on single operand. ++ adds 1 to operand and -- subtracts 1 to operand respectively. For example:

Let a=5 and b=10

a++;  //a becomes 6

a--;  //a becomes 5

++a;  //a becomes 6

--a;  //a becomes 5 

Difference between ++ and -- operator as postfix and prefix

When i++ is used as prefix (like: ++var), ++var will increment the value of var and then return it but, if ++ is used as postfix (like: var++), operator will return the value of operand first and then only increment it. This can be demonstrated by an example:

#include<stdio.h>

int main(){

int c=2,d=2;

printf("%d\n",c++);//this statement displays 2 then, only c incremented by 1 to 3.

printf("%d",++c);//this statement increments 1 to c then, only c is displayed. 

return0;

}

Output

2

4

In the pre-increment, value is first incremented and then used inside the expression

               b=++y

If the value of y is 5 then the value of b is 6 because the values of y get modified before using it in the expression.

In the post-increment, value is first used in the expression then incremented.

               b = y++

If the value of y is 5 then the value of variable b is also 5 because old value is used.

In the pre-decrement value is first decremented and then used inside the expression

b = - - var

In the post-decrement old value is first used in a expression and then old value will be decrement by 1.

b = var - -;

Example:

#include <stdio.h>

#include<conio.h>

  main( )

  {

int a, b, x = 10, y =10; 

a=x --;

b=-- y;

printf("value of a : %d", a);

printf("\nvalue of b : %d", b);

getch( );

}

output :

value of a : 10

value of  b : 9

9)Ternary Operator (? :)The two token ? and : are used to represent ternary operator.

The syntax of ternary operator is 

(condition)?(statement if condition is true):(statement if condition is false)

Example

(a % 2==0)? (printf (“even number”)): (printf(“odd number”));

Expression: An expression is a combination of variables, constants and operators written according to the syntax of C language. The expression without semicolon is called an expression.

If we place semicolon at the last of the expression convert into a statement.

Algebraic Expression	C Expression	Name of Expression
ab-c	a*b-c	Arithmetic
a=b&c	a=b&c	Logical
i=ptr/100	i=p*t*r/100	Arithmetic

Type Casting

It is the way to convert a variable from one data type to another data type. In general, fundamental data types can be converted.

There are 2 types of type casting: 

1)     Implicit type casting: This is performed by the compiler automatically. The conversion of data is performed either compilation or run time.

/*Example of implicit type casting*/

#include <stdio.h>

#include<conio.h>

main ( ) 

{

               int p,t,r,i;

               printf(“\n Enter principal, time and rate:”);

               scanf(“%d%d%d”,&p,&t,&r);

               i=p*t*r/100.00; // type casting

               printf(%d”,i); 

getch( );

}

Output: Enter principal, time and rate: 2000 1 1

20

2)     Explicit Type casting: It is explicitly defined within a program (instead of being done by the compiler for implicit type conversion).

Example:

#include<stdio.h>

#include <conio.h>

               main( ) {

               float x =  2.345;

               int i;

               i= int (x);

printf(“from float x = % f  i=%d “, x, i);

getch ( );

} 

Output: from float x = 2.345000 i=2 

Example 2: 

               double da = 3.3;

               double da = 3.3;

               double da = 3.4;

int result = (int)da + (int)db +(int)dc ; // result == 9