Enumeration (enum)

Introduction

enum defines named integer constants — improves readability over raw numbers.

Understanding the topic

Default values Start at 0 unless specified.

Custom values enum { A = 1, B = 5, C = 6 };

• Default values — Start at 0 unless specified.
• Custom values — enum { A = 1, B = 5, C = 6 };.

Step-by-step explanation

1. Default values — Start at 0 unless specified.
2. Custom values — enum { A = 1, B = 5, C = 6 };.

Syntax reference

Syntax reference:

enum Name { IDENT = value, ... };

Informative example

Example program:

#include <stdio.h>

enum Day { MON, TUE, WED };

int main(void) {
    enum Day d = WED;
    printf("%d\n", d);
    return 0;
}

2

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:

• enum for menu choices
• Switch on enum value

Summary

Enumeration (enum) in C — Readable names for integral constants.