Merge Sort

C Program For Merge Sort
Source Code:


#include<stdio.h>
#include<conio.h>


void show(int A[20],int l,int u)
{
  int i;
  printf("\n");
  for(i=l;i<=u;i++)
  {
     printf("  %d",A[i]);
  }
}

void merge(int *A,int l,int mid,int u)
{
   int i,j,k,B[20];
   i=l;
   j=mid+1;
   k=1;
   while(i<=mid && j<=u)
   {
      if(A[i]<A[j])
      {
  B[k]=A[i];
  i++;
      }
      else
      {
  B[k]=A[j];
  j++;
      }
      k++;
   }
   while(i<=mid)
   {
      B[k]=A[i];
      i++;
      k++;
   }
   while(j<=u)
   {
      B[k]=A[j];
      j++;
      k++;
   }
   k=l;
   i=1;
   while(k<=u)
   {
     A[k]=B[i];
     k++;
     i++;
   }
}

void merge_sort(int *A,int l,int u)
{
   int mid;
   if(l<u)
   {
      mid=(l+u)/2;
      merge_sort(A,l,mid);
      merge_sort(A,mid+1,u);
      merge(A,l,mid,u);
   }

}


void main()
{
  int A[20],n,item,i,ch,l,u;
  clrscr();
  printf("\nEnter upper bound and lower bound:");
  scanf("%d,%d",&l,&u);
  for(i=l;i<=u;i++)
  {
     printf("\nEnter element %d :",i);
     scanf("%d",&A[i]);
  }
  merge_sort(A,l,u);
   printf("\nAfter sorting the array is:\n");
   show(A,l,u);
  getch();
}