下面程序的运行结果为（ ）。
#include <iostream> int query(int n, int *a, int x) { int l = 0, r = n; while (l < r) { int mid = l + (r - l) / 2; if (a[mid] >= x) r = mid; else l = mid + 1; } if (l == n) return -1; return l;} int main() { int n = 10; int x = 3; int num[] = {1, 2, 2, 3, 3, 4, 5, 5, 6, 7}; std::cout << query(n, num, x) << "\n"; return 0;}