Beginner C/C++ Exercises

Reverse a String

String reversal is useful practice for indexing and in-place swaps.

What is Reverse a String?

String reversal is useful practice for indexing and in-place swaps.

Reverse text without changing its characters.

Important points

Compile with warnings enabled and fix every warning.
Know the lifetime and type of every value.
Validate input and keep array bounds explicit.

C and C++ code examples

Run code →

main.c

#include <stdio.h>
#include <string.h>
int main(void) {
    char text[] = "CodeUtility"; size_t length = strlen(text);
    // Swap mirrored characters in place.
    for (size_t i = 0; i < length / 2; ++i) {
        char temporary = text[i]; text[i] = text[length - 1 - i]; text[length - 1 - i] = temporary;
    }
    puts(text);
}

Expected output

ytilitUedoC

C++

Run code →

main.cpp

#include <algorithm>
#include <iostream>
#include <string>
int main() {
    std::string text = "CodeUtility";
    // reverse applies swaps across the selected range.
    std::reverse(text.begin(), text.end());
    std::cout << text << '\n';
}

Expected output

ytilitUedoC

C and C++ comparison

Swap mirrored characters until the two indexes meet in the center.

C exposes small procedural APIs and makes representation details explicit.

C++

C++ retains the low-level model while adding safer library types and abstractions.

Practice exercises

Run both versions, then modify them to observe the different language guarantees.

Add invalid and boundary-value inputs.
Compile with -Wall -Wextra -Wpedantic.
Move reusable declarations into a header and implementation file.