Program to Implement Quick Sort

#include <stdio.h>

#include <conio.h>

void quicksort (int a[], int low, int high);

int partition(int a[], int low, int high);

int a[5] = {55, 1, 78, 13, 45};

void main( )

{

clrscr();

int i, n;

printf("\nOriginal array");

for(i=0; i < 5; i++)

printf("%4d", a[i]);

quicksort(a, 0, 4);

printf("\nThe sorted array is \n");

for(i=0; i < 5; i++)

printf("%4d", a[i]);

getch();

}

void quicksort (int a[], int low, int high)

{

int j;

if (low < high)

{

j = partition(a,low, high);

quicksort (a, low, j-1);

quicksort(a, j+1, high);

}

}

int partition(int a[], int low, int high)

{

int i, j, temp, key;

key = a[low];

i = low + 1;

j = high;

while (1)

{

while (i < high && key >= a[i])

i++;

while (key < a[j])

j--;

if (i < j)

{

temp = a[i];

a[i] = a[j];

a[j] = temp;

}

else

{

temp = a[low];

a[low] = a[j];

a[j] = temp;

}

return j;

}

}