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Logical Operator in C -smartduniya

Logical Operator in c

Introducing to C Logical Opeartors

You use C logical operators to connect expressions and / or variables to form compound conditions. The C logical expression return an integer (int). The result has value 1 if the expression is evaluated to true otherwise it return 0.  C uses the following symbols for the boolean operations AND, OR ,and NOT.

Operator Meaning
&& logical AND
|| logical OR
! logical NOT


The AND operator (&&) and OR operator (||) has essential peculiarity:
  • The || operator, their operands are evaluated in order from left to right, and if the value of the left operand is sufficient to determine the result of the operation, then the right operand is not evaluated at all.
  • The operator && evaluates the right operand only if the left operand yields 1;

The following table illustrates the truth table of the logical operators:


a b a&&b a||b !a
True True True True False
True False False True False
False True False True True
False False False False True

Example of C Logical Operators

 The following program illustrate the C logical operators:


#include <stdio.h>
#include <stdlib.h>
int main(int argc, char** argv) {
int x = 10; int y = 15;

int z = 20;
if (x < y && y < z) {
printf("x > y && y < z\n");

if (x > y || y < z) {

printf("x > y || y < z\n");


if (!(x > y)) {

printf("!(x > y)\n");

return (0);


Below is the output of the C logical operators demo program:

x > y && y < z
x > y || y < z
!(x > y)

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