binary_search.c

#include <stdio.h>
int main()
{
	int c, first, last, mid, n, key, arr[100];

	printf("Enter number of elements\n");
	scanf("%d",&n);

	printf("Enter %d integers\n", n);

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

	printf("Enter value to find\n");
	scanf("%d", &key);

	first = 0;
	last = n - 1;
	mid = (first+last)/2;

	while (first <= last) {
		if (arr[mid] < key)
			first = mid + 1; 
		else if (arr[mid] == key) {
			printf("%d found at location %d.\n", key, mid+1);
			break;
		}
		else
			last = mid - 1;
		mid = (first + last)/2;
	}
	if (first > last)
		printf("Not found! %d is not present in the list.\n", key);
	return 0; 
}