binary search

binary search by while

#include<stdio.h>
int main()
{
  int i, n;

  scanf("%d",&n);

  int ara[n+1];

  for(i=0;i<n;i++)scanf("%d",&ara[i]);


  int key,cnt=0;

  scanf("%d",&key);

  int  b=0;
  int  e=n-1;
  int  mid=(b+e)/2;
//printf("kk");
  while(b<=e)
  {
  // printf("%d %d \n",b,e);

      if(ara[mid]==key)
      {
          cnt=1;
          break;
      }else if(ara[mid]>key)
      {
          e=mid-1;
      }else b=mid+1;


    mid=(b+e)/2;


  }


  if(cnt)printf("yes\n");
  else printf("no\n");



}


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binary search by recursion



#include<stdio.h>
int flag=0;
int binarySearch(int ara[], int b, int e, int key)
{

   // printf("%d %d \n",b,e);
    if(b>e)return -1;

   int  m=(b+e)/2;

    if(ara[m]==key)return m;
    else if(ara[m]>key)binarySearch(ara,b,m-1,key);
    else binarySearch(ara,m+1,e,key);


}

int main()
{
  int i, n;

  scanf("%d",&n);

  int ara[n+1];

  for(i=0;i<n;i++)scanf("%d",&ara[i]);


  int key;

  scanf("%d",&key);


   int  pos=binarySearch(ara,0,n-1,key);

   if(pos==-1)printf("not found\n");
   else printf(" %d \n",pos);

}