Example: Reverse String Manually in C

// Reverse String Manually
#include <stdio.h>
#include <string.h> // Required for strlen
#include <stdlib.h> // Required for malloc and free (if dynamic allocation used)

// Function to reverse a string manually
void reverseString(char* str) {
    int length = strlen(str);
    int start = 0;
    int end = length - 1;
    char temp;

    while (start < end) {
        // Step 1: Swap characters at start and end positions
        temp = str[start];
        str[start] = str[end];
        str[end] = temp;

        // Step 2: Move pointers towards the center
        start++;
        end--;
    }
}

int main() {
    // Example 1: Static string
    char str1[] = "programming";
    printf("Original string 1: %s\n", str1);
    reverseString(str1);
    printf("Reversed string 1: %s\n", str1);
    printf("\n");

    // Example 2: Dynamically allocated string
    char* str2 = (char*)malloc(sizeof(char) * 20); // Allocate memory for up to 19 chars + null
    if (str2 == NULL) {
        printf("Memory allocation failed!\n");
        return 1;
    }
    strcpy(str2, "C language"); // Copy content into allocated memory
    printf("Original string 2: %s\n", str2);
    reverseString(str2);
    printf("Reversed string 2: %s\n", str2);

    free(str2); // Free dynamically allocated memory
    str2 = NULL;

    return 0;
}