bs

#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <vector>
#include <ctime>
using namespace std;

int bs(const vector<int> &arr, int size, int x) {
    int low = 0, high = size - 1, mid;
    while (high >= low) {
        mid = low + (high - low) / 2;
        if (arr[mid] == x) {
            return mid;
        } else if (arr[mid] > x) {
            high = mid - 1;
        } else {
            low = mid + 1;
        }

    }
    return -1;
}

int main() {
    srand(time(nullptr));
    vector<int> arr(20);
    for (int i = 0; i < 20; ++i) {
        arr[i] = rand() % 100 + 1;
    }
    sort(begin(arr), end(arr));
    for (int i = 0; i < 20; ++i) {
        cout << arr[i] << " ";
    }
    cout << endl;
    cout << bs(arr, 20, 50);
    return 0;
}