​​​​​​C tutorials #11.2

Logical Operators

Following table shows all the logical operators supported by C language.
Assume variable A holds 1 and variable B holds 0, then −


&& - Called Logical AND operator.
If both the operands are non-zero, then the condition becomes true.  (A && B) is false.

|| - Called Logical OR Operator.
If any of the two operands is non-zero, then the condition becomes true.  (A || B) is true.

! - Called Logical NOT Operator.
It is used to reverse the logical state of its operand. If a condition is true, then Logical NOT operator will make it false.   !(A && B) is true.

Example

Try the following example to understand all the logical operators available in C −

#include <stdio.h>

main()
{

   int a = 5;
   int b = 20;
   int c ;

   if ( a && b )
   {
      printf("Line 1 - Condition is true\n" );
   }

   if ( a || b )
   {
      printf("Line 2 - Condition is true\n" );
   }

   /* lets change the value of  a and b */
   a = 0;
   b = 10;

   if ( a && b )
   {
      printf("Line 3 - Condition is true\n" );
   }
    else
   {
      printf("Line 3 - Condition is not true\n" );
   }

   if ( !(a && b) )
   {
      printf("Line 4 - Condition is true\n" );
   }

}

When you compile and execute the above program, it produces the following result −

Line 1 - Condition is true
Line 2 - Condition is true
Line 3 - Condition is not true
Line 4 - Condition is true