Reverse string in C: solved exercise

Reverse string in C: solved exercise

This exercise is scheduled for daily publication and follows the standard site structure: statement, solution, and expected output.

Problem statement

Solve the practical case and verify the console output.

C solution

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13

#include <stdio.h>
#include <string.h>

int main(void) {
    char s[] = "hola";
    int i = 0, j = (int)strlen(s) - 1;
    while (i < j) {
        char t = s[i]; s[i] = s[j]; s[j] = t;
        i++; j--;
    }
    printf("%s\n", s);
    return 0;
}

Expected output

1

aloh

Common mistakes

  • Not validating standard-function return values.
  • Ignoring edge cases for indices, pointers, or buffers.
  • Skipping example-based test runs before publishing.

Practical use

String reversal appears in palindrome validation, basic encoding, and classic technical interview problems.

Guided practice and full book

If you want a complete path with progressive difficulty:

FAQ

Is this exercise useful for C exams and technical interviews?

Yes. It targets patterns that commonly appear in practice assignments, technical interviews, and C programming exams.

Where can I keep practicing with more solved C exercises?

In Programming in C in 100 Solved Exercises and C Exercises. Kindle Unlimited: View on Amazon.

How should I practice this exercise type to improve faster?

Start with small inputs, run edge cases (empty, one item, max capacity), then rewrite the solution from scratch without copying.