Example: Insertion Sort Descending in C++

// Insertion Sort Descending
#include <iostream> // Required for input/output operations
#include <vector>   // Required for using std::vector

// Function to print the elements of a vector
void printArray(const std::vector<int>& arr) {
    for (int i = 0; i < arr.size(); ++i) {
        std::cout << arr[i] << " ";
    }
    std::cout << std::endl;
}

// Function to perform insertion sort in descending order
void insertionSortDescending(std::vector<int>& arr) {
    int n = arr.size(); // Get the number of elements in the array

    // Iterate from the second element to the end of the array
    for (int i = 1; i < n; ++i) {
        int key = arr[i]; // Store the current element to be inserted
        int j = i - 1;    // Initialize j to the last element of the sorted subarray

        // Move elements of arr[0..i-1], that are smaller than key,
        // to one position ahead of their current position
        while (j >= 0 && arr[j] < key) {
            arr[j + 1] = arr[j]; // Shift element to the right
            j = j - 1;           // Move to the previous element in the sorted subarray
        }
        arr[j + 1] = key; // Place the key in its correct descending position
    }
}

int main() {
    // Step 1: Initialize an unsorted vector
    std::vector<int> numbers = {5, 2, 8, 1, 9, 3, 7};

    // Step 2: Print the original array
    std::cout << "Original array: ";
    printArray(numbers);

    // Step 3: Perform insertion sort in descending order
    insertionSortDescending(numbers);

    // Step 4: Print the sorted array
    std::cout << "Sorted array (descending): ";
    printArray(numbers);

    return 0; // Indicate successful execution
}