Logical Operators in C Programming

Logical Operators in C combines multiple boolean expressions. If we want to check more than one condition, then we need logical Operators.

Logical Operators always produces boolean results, either TRUE(non-zero value) or FALSE(zero value).
There are 3 logical operators in C language AND(&&), OR(||) and NOT(!)

For Example
     "If Humidity is less than 10% and Temperature is more than 30 degree celsius"
We can implement above mentioned condition using logical operator as follows:
if((Humidity < 10) && (Temperature > 30))

Description of Logical Operators in C

  • AND : Returns true, If both operands are true otherwise false.
  • OR : Returns false If both operands are false, otherwise true.
  • NOT : Returns true if operand is false and Returns false if operand is true.
Here is the truth table of Logical Operators
A B A && B A || B !A
TRUE FALSE FALSE TRUE FALSE
TRUE TRUE TRUE TRUE FALSE
FALSE TRUE FALSE TRUE TRUE
FALSE FALSE FALSE FALSE TRUE

C Program to show use of Logical Operators

#include<stdio.h>
#include<conio.h>

int main(){

    int A = 10, B = 5;
    /*Using AND Logical Operator to combime 
      two relational expressions */
    if((A>B) && (B<7)){
        printf("Logical Expression returned TRUE\n");
    } else {
        printf("Logical Expression returned FALSE\n");
    }
    
    getch();
    return(0);
}

Output
Logical Expression returned TRUE