C++ Programming Code Examples

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Simple Quick Sort Program in C++

Simple Quick Sort Program in C++

Quicksort (sometimes called partition-exchange sort) is an efficient sorting algorithm, serving as a systematic method for placing the elements of an array in order. Quicksort is a comparison sort, meaning that it can sort items of any type for which a "less-than" relation (formally, a total order) is defined. In efficient implementations it is not a stable sort, meaning that the relative order of equal sort items is not preserved. Quicksort can operate in-place on an array, requiring small additional amounts of memory to perform the sorting.

#include <iostream>
#include<conio.h>
#include<stdlib.h>

#define maxsize 5

using namespace std;

void quick_sort(int, int);
int arr_sort[maxsize];

int main() {
    int i;

    cout << "Simple C++ Quick Sort Example - Functions and Array\n";
    cout << "\nEnter " << maxsize << " Elements for Sorting : " << endl;
    for (i = 0; i < maxsize; i++)
        cin >> arr_sort[i];

    cout << "\nYour Data   :";
    for (i = 0; i < maxsize; i++) {
        cout << "\t" << arr_sort[i];
    }

    quick_sort(0, maxsize - 1);

    cout << "\n\nSorted Data :";
    for (i = 0; i < maxsize; i++) {
        cout << "\t" << arr_sort[i];
    }

    getch();
}

void quick_sort(int f, int l) {
    int i, j, t, p = 0;

    if (f < l) {
        p = f;
        i = f;
        j = l;

        while (i < j) {
            while (arr_sort[i] <= arr_sort[p] && i < l)
                i++;
            while (arr_sort[j] > arr_sort[p])
                j--;
            if (i < j) {
                t = arr_sort[i];
                arr_sort[i] = arr_sort[j];
                arr_sort[j] = t;
            }
        }

        t = arr_sort[p];
        arr_sort[p] = arr_sort[j];
        arr_sort[j] = t;
        quick_sort(f, j - 1);
        quick_sort(j + 1, l);
    }
}