mergesort.c

#include<iostream.h>
#include<stdio.h>
#include<conio.h>
int a[10],c[10];
void merge(int , int , int );
void mergesort(int, int);
void main()
{
 int n,i
 ;
 clrscr();
 cout<<"\n Enter the value of n:\t";cin>>n;
 cout<"\n Enter the array:\t";
 for(i=0;i<n;i++) scanf("%d",&a[i]);
 mergesort(0,n-1);
 cout<<"\n Element sorted using mergesort:\t";
 for(i=0;i<n;i++) cout<<a[i]<<" ";
 getch();
}

void merge(int low, int mid, int high)
{
  int i=low,j=mid+1,k=low;
  while(i<=mid && j<=high)
  {
   if(a[i]<a[j])
    c[k++]=a[i++];
   else
    c[k++]=a[j++];
  }
  while(i<=mid) c[k++]=a[i++];
  while(j<=high) c[k++]=a[j++];
  for(int l=0;l<k;l++) a[l]=c[l];
}

void mergesort(int low, int high)
{
 int mid;
 if(low<high)
 {
  mid=(low+high)/2;
  mergesort(low,mid);
  mergesort(mid+1,high);
  merge(low,mid,high);
  }
 }