Write a ‘C’ program to sort an array elements using Merge Sort technique.

Write a ‘C’ program to sort an array elements using Merge Sort technique.


#include<stdio.h>
#include<conio.h>
int n;
void display(int a[])
{
  int i;
  printf("\n");
  for(i=0;i<n;i++)
    printf("\t%d",a[i]);
}
void merge(int a[],int low,int mid,int high)
{
  int i,j,k,b[20];
  i=low;
  j=mid+1;
  k=0;
  while ((i<=mid) && (j<=high))
  {
    if (a[i]<=a[j])
b[k++]=a[i++];
    else
b[k++]=a[j++];
  }
  while (i<=mid)
b[k++]=a[i++];
  while (j<=high)
b[k++]=a[j++];
  //copy merged element from b to a
  for(j=low,k=0;j<=high;j++,k++)
a[j]=b[k];
}
void mergesort(int a[],int low,int high)
{
  int mid;
  if(low<high)
  {
    mid=(low+high)/2;
    mergesort(a,low,mid);
    mergesort(a,mid+1,high);
    merge(a,low,mid,high);
  }
}
void main()
{
 int a[20],i;
 clrscr();
 printf("\nHow many numbers: ");
 scanf("%d",&n);
 printf("\nEnetr the unsorted numbers: ");
 for(i=0;i<n;i++)
    scanf("%d",&a[i]);
 mergesort(a,0,n-1);
 display(a);
 getch();
}