Operators in C

Types of Operators in C

An operator is a symbol that tells the compiler to perform a specific operation on one or more operands. C has a rich set of operators that can be categorized as:

• Arithmetic Operators: + - * / %
• Relational (Comparison) Operators: == != > < >= <=
• Logical Operators: && || !
• Assignment Operators: = += -= *= /= %=
• Increment/Decrement: ++ --
• Bitwise Operators: & | ^ ~ << >>
• Ternary Operator: ? :
• sizeof Operator: sizeof()

1. Arithmetic Operators

Used to perform basic mathematical operations.

#include <stdio.h>
int main() {
    int a = 10, b = 3;
    printf("a + b = %d\n", a + b);
    printf("a - b = %d\n", a - b);
    printf("a * b = %d\n", a * b);
    printf("a / b = %d\n", a / b);  // Integer division
    printf("a %% b = %d\n", a % b); // %% prints single %
    return 0;
}

2. Relational Operators

Used to compare two values. Always return 1 (true) or 0 (false).

3. Logical Operators

Used to combine multiple conditions. Return 1 (true) or 0 (false).

#include <stdio.h>
int main() {
    int marks = 85, attendance = 78;

    // Eligible if marks >= 80 AND attendance >= 75
    if (marks >= 80 && attendance >= 75) {
        printf("Eligible for scholarship\n");
    }
    // Fail if marks < 40 OR attendance < 75
    if (marks < 40 || attendance < 75) {
        printf("Not eligible\n");
    }
    return 0;
}

4. Assignment Operators

5. Increment & Decrement Operators

++ increases a value by 1, -- decreases by 1. These can be pre (before variable) or post (after variable).

#include <stdio.h>
int main() {
    int a = 5;
    printf("a++  = %d\n", a++);  // Prints 5, THEN increments to 6
    printf("a    = %d\n", a);    // Now a is 6
    printf("++a  = %d\n", ++a);  // Increments to 7, THEN prints 7
    printf("a--  = %d\n", a--);  // Prints 7, THEN decrements to 6
    printf("--a  = %d\n", --a);  // Decrements to 5, THEN prints 5
    return 0;
}

6. Ternary Operator ( ? : )

A short form of if-else. Syntax: condition ? value_if_true : value_if_false

#include <stdio.h>
int main() {
    int marks = 75;
    char *result = (marks >= 40) ? "Pass" : "Fail";
    printf("Result: %s\n", result);

    int a = 10, b = 20;
    int max = (a > b) ? a : b;
    printf("Max: %d\n", max);
    return 0;
}

Operator Precedence (Priority)

When an expression has multiple operators, precedence determines which gets evaluated first. Higher precedence = evaluated first.

Example: 2 + 3 * 4 → 3 * 4 = 12 first, then 2 + 12 = 14 (not 20!).

Use parentheses () to override precedence: (2 + 3) * 4 = 20.

Summary

• Arithmetic: + - * / % — basic math operations
• Relational: == != > < — compare values, return 0 or 1
• Logical: && || ! — combine conditions
• Assignment: = += -= — assign values
• Increment/Decrement: ++ -- — increase/decrease by 1
• Ternary: ? : — one-line if-else
• Don't confuse = (assignment) with == (comparison)