Example: qsort Strings Alphabetical in C

// qsort Strings Alphabetical
#include <stdio.h>
#include <stdlib.h> // For qsort
#include <string.h> // For strcmp

// Comparison function for strings (alphabetical order)
int compareStrings(const void *a, const void *b) {
    // The elements of the array are char*, so a and b are pointers to char*
    const char *str_a = *(const char **)a; // Cast void* to char** and then dereference to get char*
    const char *str_b = *(const char **)b; // Cast void* to char** and then dereference to get char*
    return strcmp(str_a, str_b); // Use strcmp for string comparison
}

int main() {
    // Step 1: Initialize an array of strings (array of char pointers)
    char *fruits[] = {"banana", "apple", "grape", "orange", "kiwi", "pineapple"};
    int n = sizeof(fruits) / sizeof(fruits[0]);

    printf("Original strings:\n");
    for (int i = 0; i < n; i++) {
        printf("- %s\n", fruits[i]);
    }
    printf("\n");

    // Step 2: Sort the array of strings
    qsort(fruits, n, sizeof(char *), compareStrings);

    printf("Sorted strings (alphabetical):\n");
    for (int i = 0; i < n; i++) {
        printf("- %s\n", fruits[i]);
    }
    printf("\n");

    return 0;
}