Lab Cycle 1 — Arrays & Searching

#include <iostream>
using namespace std;

int binarySearch(int arr[], int l, int r, int key) {
    while (l <= r) {
        int mid = l + (r - l) / 2;
        if (arr[mid] == key) return mid;
        if (arr[mid] < key) l = mid + 1;
        else r = mid - 1;
    }
    return -1;
}

int main() {
    int arr[] = {10, 20, 30, 40, 50};
    int key = 40;
    int result = binarySearch(arr, 0, 4, key);
    cout << "Found at index " << result;
    return 0;
}