Operators

Introduction

Operators combine values — arithmetic for math, relational and logical for decisions, bitwise for flags, and compound assignment for updates in place.

Understanding the topic

Arithmetic + - * / % — modulo only for integers.

Relational & logical Compare values; short-circuit && and ||.

Increment/decrement ++i prefix, i++ postfix — know the difference.

• Arithmetic — + - * / % — modulo only for integers.
• Relational & logical — Compare values; short-circuit && and ||.
• Increment/decrement — ++i prefix, i++ postfix — know the difference.

Step-by-step explanation

1. Arithmetic — + - * / % — modulo only for integers.
2. Relational & logical — Compare values; short-circuit && and ||.
3. Increment/decrement — ++i prefix, i++ postfix — know the difference.

Informative example

Example program:

#include <stdio.h>

int main(void) {
    int a = 14, b = 5;
    printf("add=%d rem=%d same=%d\n", a+b, a%b, a==b);
    return 0;
}

add=19 rem=4 same=0

Execution workflow

Best practices

• Enable warnings: gcc -Wall -Wextra -std=c11 source.c -o app
• Give every variable a defined value before it is read.
• Stay inside array bounds — C will not stop you from over-running a buffer.

Common mistakes

• Reading uninitialized storage — behavior is undefined.
• Dismissing compiler warnings instead of fixing root causes.
• Ignoring NULL returns from malloc, fopen, and similar APIs.

Hands-on exercise

Practice problems:

• Evaluate compound expressions
• Use bitwise & | ^ on integers

Summary

Operators in C — Math, comparison, logic, bitwise, and assignment operators.