binary_search_recursion.c

#include<stdio.h>
#include<stdlib.h>
#define size 10

int binsearch(int[], int, int, int);

int main() {
   int num = 100, i, key, position;
   int low, high, list[num];

   for (i = 0; i < num; i++) {
	list[i] = rand()%100;
   }


   low = 0;
   high = num - 1;

   printf("\nEnter element to be searched : ");
   scanf("%d", &key);

   position = binsearch(list, key, low, high);

   if (position != -1) {
      printf("\nNumber present at %d", (position + 1));
   } else
      printf("\n The number is not present in the list");
   return (0);
}

// Binary Search function
int binsearch(int a[], int x, int low, int high) {
   int mid;

   if (low > high)
      return -1;

   mid = (low + high) / 2;

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