Problem

Given a sorted array of integers, write a function that returns the index of a given target value. If the target value is not present in the array, the function should return -1.
Example input: [1, 2, 3, 4, 5, 6, 7], target = 5
Example output: 4

Solution

#include <iostream>
#include <vector>

using namespace std;

int binarySearch(vector<int> arr, int target) {
    int left = 0;
    int right = arr.size() - 1;
    int mid;

    while (left <= right) {
        mid = (left + right) / 2;
        if (arr[mid] == target) {
            return mid;
        } else if (arr[mid] < target) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }

    return -1;
}

int main() {
    vector<int> arr = {1, 2, 3, 4, 5, 6, 7};
    int target = 5;

    cout << binarySearch(arr, target) << endl;

    return 0;
}