Mastering Operators in C: Arithmetic, Relational, and Logical

Welcome to the third post in our “C Programming Insights” series! Now that you’re familiar with variables and data types, let’s take a deeper dive into operators—the tools that allow you to perform calculations, compare values, and control program flow in C.

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What Are Operators in C?

Operators are symbols that perform operations on variables and values. For example:

int result = 10 + 5;

Here, + is the arithmetic operator used to add two values.

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Types of Operators in C

1. Arithmetic Operators

Used to perform basic mathematical operations:

Operator	Description	Example

+

Addition

a + b

-

Subtraction

a - b

*

Multiplication

a * b

/

Division

a / b

%

Modulus (remainder)

a % b

Example Code:

int a = 10, b = 3;  
printf("Addition: %d\n", a + b);  
printf("Remainder: %d\n", a % b);  

Relational Operators

Used to compare two values, resulting in true (1) or false (0).

Operator	Description	Example
==	Equal to	a == b
!=	Not equal to	a != b
>	Greater than	a > b
<	Less than	a < b
>=	Greater than or equal to	a >= b
<=	Less than or equal to	a <= b

Example Code:

int x = 5, y = 10;  
printf("x > y: %d\n", x > y);  // Output: 0 (false) 

3. Logical Operators

Used to combine or invert conditions.

Operator	Description	Example
&&	Logical AND (true if both true)	(a > 0) && (b > 0)
`		`
!	Logical NOT (invert truth value)	!(a > b)

Example Code:

int a = 10, b = -5;  
printf("Logical AND: %d\n", (a > 0) && (b > 0));  // Output: 0 (false)

Combining Operators in a Program

Here’s how you can use different types of operators together:

Example Program:

#include <stdio.h>  

int main() {  
    int a = 15, b = 10, c = 5;  

    // Arithmetic  
    int sum = a + b + c;  

    // Relational  
    int isGreater = sum > 20;  

    // Logical  
    int check = (a > b) && (b > c);  

    printf("Sum: %d\n", sum);  
    printf("Is sum greater than 20? %d\n", isGreater);  
    printf("Logical check: %d\n", check);  

    return 0;  
}  

Output:

Sum: 30  
Is sum greater than 20? 1  
Logical check: 1  

Programming Tips for Operators

1. Use parentheses () to make expressions clearer and avoid operator precedence issues.
2. Be careful with integer division; it truncates the decimal part.
   • Example: 5 / 2 = 2 (not 2.5).
3. Always test your conditions with edge cases to avoid logical errors.

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Practice Problem

Write a program that:

1. Takes two integers as input.
2. Uses relational and logical operators to check if both numbers are positive.
3. Displays the larger of the two numbers.

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What’s Next?

In the next post, we’ll explore control structures in C, such as if, else, and loops, to create more dynamic and interactive programs.

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