#include <stdio.h>

	// Function Prototypes
	int binSearch(int arr[], int target, int len);

	// Returns 1 if target is in array, otherwise returns 0
	int binSearch(int arr[], int target, int len) {
		int left = 0;
		int right = len - 1;
		int mid;
		while (left <= right) {
			mid = (left + right) / 2;
			if (arr[mid] == target)
				return 1;
			if (target < arr[mid])
				right = mid - 1;
			else
				left = mid + 1;
		}
		return 0;
	}

	int main(void) {
		int len = 20;
		int arr[] = {3,  6,  7,  11, 25, 32,  33,  33,  46,  52,
								 79, 83, 88, 91, 94, 101, 107, 112, 122, 148};
		int choice = 0;
		while (choice >= 0) {
			printf("Enter positive integer to see if it exists in the array\n(Enter "
						 "negative value to exit)\n:");
			scanf("%d", &choice);
			if (choice < 0)
				break;
			printf("%d is %sin the array.\n\n", choice,
						 binSearch(arr, choice, len) ? "" : "NOT ");
		}
		return 0;
	}