Relational Operators in C

Relational operators in C are used to compare two values or expressions and determine the relationship between them. They are commonly used in decision-making statements such as if, if-else, while, and for loops to control the flow of a program based on conditions.

• Used to compare two operands or expressions.
• Always return 1 (true) or 0 (false).
• Commonly used in conditional and looping statements.

Types of C Relational Operators

There are a total of 6 relational operators in C language. There are:

1. Equal to operator (==)

The C equal to operator (==) is a relational operator that is used to check whether the two given operands are equal or not.

• Equal to operator is a binary operator hence it requires two operands to perform the comparison.
• If the two values are equal, it returns true. Otherwise, it returns false.

Syntax

operand1 == operand2

For example, 5==5 will return true.

2. Not equal to operator (!=)

The C not equal (==) to operator is another relational operator used for checking whether the two given operands are equal or not.

• It is also a binary operator, requiring two operands to perform the comparison.
• It is the exact boolean complement of the '==' operator which returns true if the two values are not equal, false otherwise.

Syntax

operand1 != operand2

For example, 5!=5 will return false.

3. Greater than operator (>)

The greater than operator is a relational operator in C that checks whether the first operand is greater than the second operand or not.

• If the operand first is greater than the operand2, it returns true. Otherwise, it returns false.
• This operator is used to make decisions or create conditions based on the relative magnitude of two values.

Syntax

operand1 > operand2

For example, 6>5 will return true.

4. Less than operator (<)

The less than operator is a relational operator in C that checks whether the first operand is lesser than the second operand.

• If the operand first is less than the operand2, it returns true. Otherwise, it returns false.
• This operator is also used to make decisions or create conditions based on the relative magnitude of two values.

Syntax

operand1 < operand2

For example, 6<5 will return false.

Note: The greater than and less than operator are not equal to the complement of each other.

5. Greater than or equal to operator (>=)

The greater than or equal to the operator is a relational operator in C that checks whether the first operand is greater than or equal to the second operand.

• It is a binary operator.
• If the first operand is greater than or equal to the second operand, it returns true. Otherwise, it returns false.

Syntax

operand1 >= operand2

For example, 5>=5 will return true.

6. Less than or equal to the the operator (<=)

The less than or equal to the operator is a relational operator in C that checks whether the first operand is less than or equal to the second operand.

• It is a binary operator.
• If the first operand is less than or equal to the second operand, it returns true. Otherwise, it returns false.

Syntax

operand1 <= operand2

For example, 5<=5 will also return true.

Example of Relational Operator in C

#include <stdio.h>

int main()
{
    int a = 10, b = 4;

    // greater than example
    if (a > b)
        printf("a is greater than b\n");
    else
        printf("a is less than or equal to b\n");

    // greater than equal to
    if (a >= b)
        printf("a is greater than or equal to b\n");
    else
        printf("a is lesser than b\n");

    // less than example
    if (a < b)
        printf("a is less than b\n");
    else
        printf("a is greater than or equal to b\n");

    // lesser than equal to
    if (a <= b)
        printf("a is lesser than or equal to b\n");
    else
        printf("a is greater than b\n");

    // equal to
    if (a == b)
        printf("a is equal to b\n");
    else
        printf("a and b are not equal\n");

    // not equal to
    if (a != b)
        printf("a is not equal to b\n");
    else
        printf("a is equal b\n");

    return 0;
}

a is greater than b
a is greater than or equal to b
a is greater than or equal to b
a is greater than b
a and b are not equal
a is not equal to b

Explanation: In this program, different relational operators are used to compare the values of a (10) and b (4). Since 10 is greater than 4, the conditions a > b, a >= b, and a != b evaluate to true, while a < b, a <= b, and a == b evaluate to false. Based on these results, the corresponding messages are printed to the console.

Advantages of Relational Operators in C

• Enable Decision Making: Help programs make decisions using conditions in if, if-else, and switch statements.
• Support Loop Control: Used in loops such as while, for, and do-while to control execution.
• Easy Value Comparison: Allow comparison of variables, constants, and expressions efficiently.
• Return Simple Results: Produce either 1 (true) or 0 (false), making conditions easy to evaluate.
• Improve Program Logic: Help implement validation, searching, sorting, and other logical operations.
• Increase Code Readability: Make conditional expressions concise and easy to understand.
• Widely Used in Algorithms: Essential for implementing comparison-based algorithms and data processing tasks.