Logical Operators

These operators are used to perform logical operations on the given expressions. When we use if, for, while then use one condition at once time what happens if we examine condition more than one? In this case, we use logical operators. So logical operators are used to combine two or more condition. There are 3 logical operators in C language. They are, logical AND (&&), logical OR (||) and logical NOT (!).

Example

/* A C program for logical operator */

#include <stdio.h>
main()
{
int num1 = 5;
int num2 = 20;
int num3 ;
if ( num1 && num2 )
{
printf("Line 1 - Condition is true\n" );
}
if ( num1 || num2 )
{
printf("Line 2 - Condition is true\n" );
}
/* lets change the value of a and b */
num1 = 0;
num2 = 10;
if ( num1 && num2 )
{
printf("Line 3 - Condition is true\n" );
}
else
{
printf("Line 3 - Condition is not true\n" );
}
if ( !(num1 && num2) )
{
printf("Line 4 - Condition is true\n" );
}
}

Output:

Line 1 - Condition is true

Line 2 - Condition is true

Line 3 - Condition is not true

Line 4 - Condition is true