- C Introduction
- C - Features
- C - Applications
- C - Preprocessor
- C - Preprocessor Directives
- C - Type Definitions
- C - Function Prototypes
- C - Header Files and Libraries
- C - Main Function
- C Program Elements
- C - Datatypes
- C - Constants
- C - Operators
- C - Assignment Operator
- C - Arithmetic Operator
- C - Relational Operator
- C - Sample Program to illustrate C relational operator
- C - Logical Operator
- C - Sample Program to demonstrate logical operators
- C - Increment and Decrement Operator
- C - Sample Program to illustrate pre increment
- C - Sample Program to illustrate post increment
- C - Bitwise Operator
- C - Sample Program to illustrate bitwise Operator
- C - Conditional Operator
- C - Comma Operator
- C - Sizeof Operator
- C - Typecast Operator
- C - Operator Precedence and Associativity
- C - Identifiers
- C - Keywords
- C Statements
- C - if-else statement
- C - else-if ladder statement
- C - Switch statement
- C - Sample Program to illustrate switch statement
- C - While Statements
- C - Sample Program to illustrate while loop
- C - do-while Statement
- C - for Statement
- C - Sample Program to illustrate for-loop
- C - Break statement
- C - Continue statement
C - Relational Operator
Relational Operators in C
Introduction to Relational Operators in C
In the C programming language, relational operators play a crucial role in decision-making and logical evaluation. They are used to compare two operands and determine the relationship between them. The result of a relational expression in C is either true or false, represented internally as 1 for true and 0 for false.
Understanding C relational operators is essential for writing conditional statements, loops, and complex logical expressions. Almost every real-world C program relies heavily on relational operators to control program flow. For beginners and advanced learners alike, mastering these operators is a foundational step toward becoming proficient in C programming.
What Are Relational Operators in C?
Relational operators in C are symbols that compare two values or expressions. They evaluate the relationship between operands such as equality, inequality, greater than, less than, or equality with boundary conditions.
The output of any relational operation is an integer value:
- 1 – if the condition is true
- 0 – if the condition is false
These operators are widely used in:
- Conditional statements like if, if-else, and switch
- Looping structures such as for, while, and do-while
- Logical expressions combined with logical operators
- Decision-making algorithms
List of Relational Operators in C
The C language provides six relational operators. Each operator has a specific purpose and syntax.
| Operator | Name | Description |
|---|---|---|
| < | Less than | Returns true if left operand is less than right operand |
| > | Greater than | Returns true if left operand is greater than right operand |
| <= | Less than or equal to | Returns true if left operand is less than or equal to right operand |
| >= | Greater than or equal to | Returns true if left operand is greater than or equal to right operand |
| == | Equal to | Returns true if both operands are equal |
| != | Not equal to | Returns true if operands are not equal |
Understanding Each Relational Operator in Detail
Less Than Operator (<)
The less than operator checks whether the value of the left operand is strictly smaller than the value of the right operand. It is commonly used in loops and range-based conditions.
#include <stdio.h>
int main() {
int a = 5, b = 10;
if (a < b) {
printf("a is less than b");
}
return 0;
}
In this example, the condition evaluates to true because 5 is less than 10.
Greater Than Operator (>)
The greater than operator compares two operands and returns true if the left operand is greater than the right operand.
#include <stdio.h>
int main() {
int x = 20, y = 15;
if (x > y) {
printf("x is greater than y");
}
return 0;
}
This operator is frequently used in decision-making logic and validation checks.
Less Than or Equal To Operator (<=)
The less than or equal to operator checks whether the left operand is either less than or exactly equal to the right operand.
#include <stdio.h>
int main() {
int marks = 40;
if (marks <= 50) {
printf("Needs improvement");
}
return 0;
}
This operator is especially useful in grading systems, limits checking, and boundary conditions.
Greater Than or Equal To Operator (>=)
The greater than or equal to operator returns true when the left operand is greater than or equal to the right operand.
#include <stdio.h>
int main() {
int age = 18;
if (age >= 18) {
printf("Eligible to vote");
}
return 0;
}
This operator is widely used in eligibility checks and threshold comparisons.
Equal To Operator (==)
The equal to operator checks whether both operands have the same value. It is important not to confuse this operator with the assignment operator.
#include <stdio.h>
int main() {
int num = 10;
if (num == 10) {
printf("Number is equal to 10");
}
return 0;
}
A common beginner mistake is using a single equals sign instead of double equals.
Not Equal To Operator (!=)
The not equal to operator checks whether two operands are different.
#include <stdio.h>
int main() {
int password = 1234;
if (password != 1111) {
printf("Incorrect password");
}
return 0;
}
This operator is often used in validation, error checking, and loop termination conditions.
Relational Operators and Decision Making in C
Relational operators are a fundamental part of decision-making in C programming. They are most commonly used inside conditional statements.
Using Relational Operators with if Statement
#include <stdio.h>
int main() {
int temperature = 35;
if (temperature > 30) {
printf("It is a hot day");
}
return 0;
}
Using Relational Operators with if-else Statement
#include <stdio.h>
int main() {
int number = 7;
if (number % 2 == 0) {
printf("Even number");
} else {
printf("Odd number");
}
return 0;
}
Relational Operators in Loops
Relational operators are heavily used in loop conditions to control iteration.
Using Relational Operators in for Loop
#include <stdio.h>
int main() {
int i;
for (i = 1; i <= 5; i++) {
printf("%d\n", i);
}
return 0;
}
Using Relational Operators in while Loop
#include <stdio.h>
int main() {
int count = 1;
while (count < 4) {
printf("Count: %d\n", count);
count++;
}
return 0;
}
Relational Operators with Different Data Types
C relational operators can be applied to various data types such as integers, floating-point numbers, and characters. When different data types are involved, implicit type conversion occurs.
#include <stdio.h>
int main() {
int a = 5;
float b = 5.0;
if (a == b) {
printf("a and b are equal");
}
return 0;
}
Common Mistakes with Relational Operators in C
- Confusing assignment operator with equality operator
- Using relational operators incorrectly in complex expressions
- Ignoring operator precedence
- Incorrect comparisons with floating-point values
Relational operators in C form the backbone of logical decision-making and program control. They allow programmers to compare values, make informed decisions, and execute different code paths based on conditions. By understanding and practicing these operators, learners can write more efficient, readable, and reliable C programs.
Mastery of C relational operators is essential for anyone aiming to build a strong foundation in C programming and move forward to advanced concepts.
