## Wednesday, October 5, 2011

### Write C++ programs for sorting a given list of elements in ascending order using Merge sort

Write C++ programs for sorting a given list of elements in ascending order using Merge sort the following sorting methods */

#include<iostream>
#include<conio.h>
using namespace std;
void mergesort(int *,int,int);
void merge(int *,int,int,int);
int a[20],i,n,b[20];

main()
{
cout <<"\n enter no of elements";
cin >> n;
cout <<"enter the elements";
for(i=0;i<n;i++)
cin >> a[i];
mergesort(a,0,n-1);
cout <<" numbers after sort";
for(i=0;i<n;i++)
cout << a[i] << " ";
getch();
}

void mergesort(int a[],int i,int j)
{
int mid;
if(i<j)
{
mid=(i+j)/2;
mergesort(a,i,mid);
mergesort(a,mid+1,j);
merge(a,i,mid,j);
}
}
void merge(int a[],int low,int mid ,int high)
{
int h,i,j,k;
h=low;
i=low;
j=mid+1;
while(h<=mid && j<=high)
{
if(a[h]<=a[j])
b[i]=a[h++];
else
b[i]=a[j++];
i++;
}

if( h > mid)
for(k=j;k<=high;k++)
b[i++]=a[k];
else
for(k=h;k<=mid;k++)
b[i++]=a[k];

cout <<"\n";
for(k=low;k<=high;k++)
{  a[k]=b[k];
cout << a[k] <<" ";
}

}

OUTPUT
N enter no of elements8 12 5 61 60 50 1 70 81
enter the elements
5 12
60 61
5 12 60 61
1 50
70 81
1 50 70 81
1 5 12 50 60 61 70 81  numbers after sort1 5 12 50 60 61 70 81