Assignment 7

ASSIGNMENT NO.7
TITLE: Implementation of quick sort.


#include<stdio.h>
void swap (int a[], int left, int right)
{
	int temp;
	temp=a[left];
	a[left]=a[right];
	a[right]=temp; 
}


voidprintarr(int a[], int n);

void quicksort( int a[], int low, inthigh,int n )
{
	int pivot;
	if ( high > low )
	{
		pivot = part( a, low, high );
		printf("\n%d is pivot element\n",a[pivot]);
		printarr(a,n);
		quicksort( a, low, pivot-1,n );
	
		quicksort( a, pivot+1, high,n );
	}
} 
int part( int a[], int low, int high )
{
	int left, right;
	intpivot_item;
	int pivot = left = low; 
	pivot_item = a[low]; 
	right = high;
	while ( left < right ) 
	{
	
		while( a[left] <= pivot_item ) 
		{
			left++;
		}
		
		while( a[right] >pivot_item ) 
		{
			right--;
		}
		if ( left < right ) 
		{
			swap(a,left,right);
		}
	}

	a[low] = a[right];
	a[right] = pivot_item;
	return right;
}
int main()
{
	int a[50], i, n;
	printf("\nEnter no. of elements: "); 
	scanf("%d", &n);
	printf("\nEnter the elements: \n");
	for (i=0; i<n; i++)
		scanf ("%d", &a[i]);
	printf("\nUnsorted elements: \n");
	printarr(a,n);
	quicksort(a,0,n-1,n);
	printf("\nSorted elements: \n");
	printarr(a,n);
}


void printarr(int a[], int n)
{
	int i;
	printf("\n");
	for (i=0; i<n; i++)
		printf(" %d ", a[i]);
	printf("\n");
}