TheAlgorithms-C-Plus-Plus/sorting/quick_sort.cpp

/*
 *
 *      copyright The Algorithms
 *      Author - 
 *      Correction - ayaankhan98
 *
 */

#include <cstdlib>
#include <iostream>

int partition(int arr[], int low, int high) {
    int pivot = arr[high];    // pivot
    int i = (low - 1);        // Index of smaller element

    for (int j = low; j < high; j++) {
        // If current element is smaller than or
        // equal to pivot
        if (arr[j] <= pivot) {
            i++;   // increment index of smaller element
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }
    int temp = arr[i + 1];
    arr[i + 1] = arr[high];
    arr[high] = temp;
    return (i + 1);
}

void quickSort(int arr[], int low, int high) {
    if (low < high) {
        int p = partition(arr, low, high);
        quickSort(arr, low, p - 1);
        quickSort(arr, p + 1, high);
    }
}

void show(int arr[], int size) {
    for (int i = 0; i < size; i++)
        std::cout << arr[i] << " ";
    std::cout << "\n";
}

// Driver program to test above functions

int main() {
    int size;
    std::cout << "\nEnter the number of elements : ";
    std::cin >> size;
    int *arr = new int[size];
    std::cout << "\nEnter the unsorted elements : ";
    for (int i = 0; i < size; ++i) {
      std::cin >> arr[i];
    }
    quickSort(arr, 0, size-1);
    std::cout << "Sorted array : ";
    show(arr, size);
    return 0;
}