Logical operator in C

Logical operator in C

By Ahmad Irshad | C Programming Tutorial > Logical operaotr in C

Relational operators are used to compare between two operands. However, relational operators does not support comparison of three or more quantities.

For example, suppose you need to check range of a number. You need to check whether a number n is in between 1-100 or not. For that you must check two conditions, first check if n > 1 finally check if n < 100.

Logical operators are used to connect two or more expressions as a singal expressioin. It returns boolean value either true (1) or false (0) depending on the given expression.

There are three logical operators in C.

Operators	Description
&&	Logical AND
||	Logical OR
!	Logical NOT

Logical AND (&&) operator:

We use logical AND operator in situations when two or more conditions must be true for a decision.

Logical AND (&&) operator is a binary operator. It returns true (0) when both the conditions are satisfied. Otherwise it returns false (1). 

 

For Exmaple:

1. #include <stdio.h>
2. int main() { int x = 6, y = 3;
3. if (x < 10 && y > 2)   printf("True, since both the conditions are satisfied.");
4. else
5. printf("False, since both the conditions are not satisfied.");
6. return 0;
7. }

Logical OR || operator:

Logical OR || operator is a binary operator. It returns true (1) even if one (or both) of the conditions is satisfied. Otherwise it returns false (0). 

For Example:

1. #include <stdio.h>
2. int main() { int x = 6, y = 3;
3. if (x > 10 || y > 2)   printf("It returns true, since 2nd condition is satisfied.");
4. else
5. printf("It returns false, if both conditions are not satisfied.");
6. return 0;
7. }

Logical NOT ! operator:

Logical NOT !  is a unary operator it has only one operand. It is used to reverse the logical state of its operand. In other words, if a condition is true, then logical NOT operator will make it false. 

For Example:

1. #include <stdio.h>
2. int main() { int x = 6, y = 3;
3. if (!(x == y))   printf("It returns true, since x!=y condition is satisfied.");
4. else
5. printf("It returns false, if both conditions are not satisfied.");
6. return 0;
7. }

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