merge.c

//implementation of merge sort
#include<stdio.h>

int a[20],b[20],n;

void merging(int low,int mid,int high)
{
  int l1,l2,i;

  for(l1=low,l2=mid+1,i=low;l1<=mid && l2<=high;i++)
  if(a[l1]<=a[l2])
   b[i]=a[l1++];
  else
   b[i]=a[l2++];

   while(l1<=mid)    b[i++]=a[l1++];
   while(l2<=high)   b[i++]=a[l2++];

   for(i=low;i<=high;i++)
   	a[i]=b[i];
}

 void sort(int low,int high)
 {
    int mid;
    if(low<high)
	    {
	      mid=(low+high)/2;
	      sort(low,mid);
	      sort(mid+1,high);
	      merging(low,mid,high);
	     }
    else
	return;
 }

  main()
 { int i;
    printf("Enter N "); scanf("%d",&n);
    
    printf("Enter elements\n");
    for(i=1;i<=n;i++) scanf("%d",&a[i]);
    
	sort(1,n);
    
	printf("After sorting\n");
    for(i=1;i<=n;i++) printf("%d\n",a[i]);
 }