Binary_search.c

// C program to implement recursive Binary Search
#include <stdio.h>

// A recursive binary search function. It returns
// location of x in given array arr[l..r] is present,
// otherwise -1
int binarySearch(int arr[], int l, int r, int x)
{
	if (r >= l) {
		int mid = l + (r - l) / 2;

		// If the element is present at the middle
		// itself
		if (arr[mid] == x)
			return mid;

		// If element is smaller than mid, then
		// it can only be present in left subarray
		if (arr[mid] > x)
			return binarySearch(arr, l, mid - 1, x);

		// Else the element can only be present
		// in right subarray
		return binarySearch(arr, mid + 1, r, x);
	}
	return -1;
}

int main(void)
{
	int i, n, x;
	printf("Enter the number of elements in the array : ");
	scanf("%d",&n);
	int arr[n];
	printf("Enter the elements in the array : ");
	for(i = 0;i<n;i++){
		scanf("%d",&arr[i]);
	}
	printf("Enter the element you want to search in the array : ");
	scanf("%d", &x);
	int result = binarySearch(arr, 0, n - 1, x);
	if(result == -1)
		 printf("Element is not present in array");
	else
		 printf("Element is present at index %d", result);
	return 0;
}