DAA Lab program to perform merge sort

DAA LAB  Program 6

Write a program to perform merge sort.

#include <stdio.h>

#include<conio.h>

void mergesort(int arr[], int l, int h);

void main(void)

{

int array[100],n,i = 0;

clrscr();

printf("\t\t\tMerge Sort\n\n\n\n");

printf("Enter the number of elements to be sorted: ");

scanf("%d",&n);

printf("\nEnter the elements to be sorted: \n");

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

{

printf("\tArray[%d] = ",i);

scanf("%d",&array[i]);

}

printf("\nBefore Mergesort:");

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

{

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

}

printf("\n");

mergesort(array, 0, n - 1);

printf("\nAfter Mergesort:");

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

{

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

}

printf("\n");

getch();

}

void mergesort(int arr[], int l, int h)

{

int i = 0;

int length = h - l + 1;

int pivot  = 0;

int merge1 = 0;

int merge2 = 0;

int temp[100];

if(l == h)

return;

pivot  = (l + h) / 2;

mergesort(arr, l, pivot);

mergesort(arr, pivot + 1, h);

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

{

temp[i] = arr[l + i];

}

merge1 = 0;

merge2 = pivot - l + 1;

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

{

if(merge2 <= h - l)

{

if(merge1 <= pivot - l)

{

if(temp[merge1] > temp[merge2])

{

arr[i + l] = temp[merge2++];

}

else

{

arr[i + l] = temp[merge1++];

}

}

else

{

arr[i + l] = temp[merge2++];

}

}

else

{

arr[i + l] = temp[merge1++];

}

}

}

 OUTPUT