#include <stdio.h>

int binsearch(int x, int v[], int n);
int binsearch_original(int x, int v[], int n);

int main() {
    int v[] = {1,2,3,4,5};
    int x = 2;
    int n = 5;
    printf("%d\n%d\n", binsearch_original(x, v, n), binsearch(x, v, n));
}

int binsearch(int x, int v[], int n) {
    int low, high, mid;

    low = 0;
    high = n - 1;

    while (low < high) {
        mid = (low + high) / 2;
        if (x <= v[mid])
            high = mid;
        else
            low = mid + 1;
    }

    return (x == v[low]) ? low : -1;
}

/*
 * Find x in v[0] <= v[1] <= ... <= v[n-1]
 */
int binsearch_original(int x, int v[], int n) {
    int low, high, mid;

    low = 0;
    high = n - 1;

    while (low <= high) {
        mid = (low + high) / 2;
        if (x < v[mid])
            high = mid - 1;
        else if (x > v[mid])
            low = mid + 1;
        else // found match
            return mid;
    }

    return -1; // no match
}