quick sort function in c++ code example

Example 1: Quick Sort in c++

#include <bits/stdc++.h> 
using namespace std;  
  
 
void swap(int* a, int* b)  
{  
    int t = *a;  
    *a = *b;  
    *b = t;  
}  
  

int partition (int arr[], int low, int high)  
{  
    int pivot = arr[high];  
    int i = (low - 1);  
  
    for (int j = low; j <= high - 1; j++)  
    {  
     
        if (arr[j] < pivot)  
        {  
            i++;  
            swap(&arr[i], &arr[j]);  
        }  
    }  
    swap(&arr[i + 1], &arr[high]);  
    return (i + 1);  
}  
  

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

void printArray(int arr[], int size)  
{  
    int i;  
    for (i = 0; i < size; i++)  
        cout << arr[i] << " ";  
    cout << endl;  
}  
  

int main()  
{  
    int arr[] = {10, 7, 8, 9, 1, 5};  
    int n = sizeof(arr) / sizeof(arr[0]);  
    quickSort(arr, 0, n - 1);  
    cout << "Sorted array: \n";  
    printArray(arr, n);  
    return 0;  
}

Example 2: quick sort predefined function in c++

#include <cstdlib>

//declare compare
int compare(const void* a, const void* b)
{
	const int* x = (int*) a;
	const int* y = (int*) b;

	if (*x > *y)
		return 1;
	else if (*x < *y)
		return -1;

	return 0;
}

//fuction used
qsort(arr,num,sizeof(int),compare);