C++ Program To Sort An Array In Descending Order

You can sort an array in descending order in C++ using the standard library function std::sort. However, since std::sort sorts in ascending order by default, you need to provide a custom comparison function to sort in descending order. Here’s an example of how to do this:

#include <iostream>
#include <algorithm>

bool compareDescending(int a, int b) {
    return a > b; // Compare in descending order
}

int main() {
    int arr[] = {5, 2, 9, 1, 5, 6};
    int n = sizeof(arr) / sizeof(arr[0]);

    std::sort(arr, arr + n, compareDescending);

    std::cout << "Array sorted in descending order: ";
    for (int i = 0; i < n; ++i) {
        std::cout << arr[i] << " ";
    }
    std::cout << std::endl;

    return 0;
}

In this code:

• We include the necessary headers <iostream> and <algorithm>.
• We define a custom comparison function compareDescending, which returns true if a should come before b in the sorted order (i.e., if a is greater than b for descending order).
• In the main function, we define an integer array arr and determine its size n.
• We use std::sort to sort the array arr in descending order by passing the compareDescending function as the third argument to std::sort.
• Finally, we print the sorted array in descending order.

After running this program, the arr array will be sorted in descending order, as specified by the custom comparison function.