Strings

Introduction

Text in C is a char array terminated by a zero byte. Length is not stored — algorithms scan until they see that sentinel.

Understanding the topic

String literal char s[] = "text"; — compiler adds '\0'.

Character access s[i] like an array; stop at '\0' when iterating.

Input caution Use fgets, not unbounded scanf for strings.

• String literal — char s[] = "text"; — compiler adds '\0'.
• Character access — s[i] like an array; stop at '\0' when iterating.
• Input caution — Use fgets, not unbounded scanf for strings.

Step-by-step explanation

1. String literal — char s[] = "text"; — compiler adds '\0'.
2. Character access — s[i] like an array; stop at '\0' when iterating.
3. Input caution — Use fgets, not unbounded scanf for strings.

Syntax reference

Syntax reference:

char str[size] = "text";

Informative example

Example program:

#include <stdio.h>

int main(void) {
    char word[] = "C strings";
    printf("%s\n", word);
    return 0;
}

C strings

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:

• Print string char by char
• Count string length manually

Summary

Strings in C — char buffers ending with a null byte.