DS7.C

//Data Structure Program 7
//Binary Search


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

int binarysearch(int a[], int low, int high, int x) {
   int mid = (low + high) / 2;
   if (low > high) return -1;
   if (a[mid] == x) return mid;

   if (a[mid] < x)
     return binarysearch(a, mid + 1, high, x);
   else
     return binarysearch(a, low, mid-1, x);
}

int main(void) {
  int a[100];
  int len, pos, search_item,i;
		system("cls");
  printf("Enter the length of the array\n");
  scanf("%d", &len);

  printf("Enter the array elements\n");
  for (i=0; i<len; i++)
    scanf("%d", &a[i]);

  printf("Enter the element to search\n");
  scanf("%d", &search_item);

  pos = binarysearch(a,0,len-1,search_item);

  if (pos < 0 )
   { printf("Cannot find the element %d in the array.\n", search_item);
   getch();}

  else
   { printf("The position of %d in the array is %d.\n", search_item, pos+1);
    getch();}
  return 0;
}