Example: Insertion Sort in Descending Order in C

// Insertion Sort in Descending Order
#include <stdio.h>

// Function to perform insertion sort in descending order
void insertionSortDescending(int arr[], int n) {
    int i, key, j;
    for (i = 1; i < n; i++) {
        key = arr[i]; // Current element to be inserted
        j = i - 1;    // Index of the last element in the sorted subarray

        // Move elements of arr[0..i-1], that are smaller than key,
        // to one position ahead of their current position.
        // This creates space for 'key' at the correct descending position.
        while (j >= 0 && arr[j] < key) { // Changed from arr[j] > key for ascending
            arr[j + 1] = arr[j];
            j = j - 1;
        }
        arr[j + 1] = key; // Place key at its correct position
    }
}

// Function to print an array
void printArray(int arr[], int size) {
    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
}

int main() {
    // Step 1: Initialize an unsorted array
    int arr[] = {12, 11, 13, 5, 6};
    int n = sizeof(arr) / sizeof(arr[0]);

    printf("Original array: ");
    printArray(arr, n);

    // Step 2: Call the insertion sort function for descending order
    insertionSortDescending(arr, n);

    printf("Sorted array (descending): ");
    printArray(arr, n);

    return 0;
}