Quick.c

#include<stdio.h>
void swap (int a[], int left, int right)
{
    int temp;
    temp=a[left];
    a[left]=a[right];
    a[right]=temp;
} //end swap
int partition( int a[], int low, int high )
{
    int left, right;
    int pivot_item;
    int pivot = left = low;
    pivot_item = a[low];
    right = high;
    while ( left < right )
    {
// Move left while item < pivot
        while( a[left] <= pivot_item )
            left++;
// Move right while item > pivot
        while( a[right] > pivot_item )
            right--;
        if ( left < right )
            swap(a,left,right);
    }
// right is final position for the pivot
    a[low] = a[right];
    a[right] = pivot_item;
    return right;
} //end partition
// void quicksort(int a[], int, int);
void quicksort( int a[], int low, int high )
{
    int pivot;
// Termination condition!
    if ( high > low )
    {
        pivot = partition( a, low, high );
        quicksort( a, low, pivot-1 );
        quicksort( a, pivot+1, high );
    }
} //end quicksort
void printarray(int a[], int);
int main()
{
    int a[50], i, n;
    printf("\nEnter no. of elements: ");
    scanf("%d", &n);
    printf("\nEnter the elements:");
    for (i=0; i<n; i++)
        scanf ("%d", &a[i]);
    printf("\nUnsorted input elements:");
    printarray(a,n);
    quicksort(a,0,n-1);
    printf("\nSorted output elements:");
    printarray(a,n);
} //end main
void printarray(int a[], int n)
{
    int i;
    for (i=0; i<n; i++)
        printf(" %d ", a[i]);
    printf("\n");
}//end printarray