binarysearch.cpp

#include <iostream>
#include <vector>

using namespace std;

void Binary_Search(const vector<int> &numbers, int value);

int main() {

    vector<int> my_numbers;

    for (int i = 0; i < 4000000; i++) my_numbers.push_back(i);

    cout << "Size of vector my_nymbers :" << my_numbers.size() << endl;
    Binary_Search(my_numbers, 2);
    Binary_Search(my_numbers, 23);
    Binary_Search(my_numbers, 234);
    Binary_Search(my_numbers, 7655);
    Binary_Search(my_numbers, 10101);
    Binary_Search(my_numbers, 895543);
    Binary_Search(my_numbers, 3785111);

    return 0;
}

void Binary_Search(const vector<int> &my_numbers, int key) {

    int iteration = 0, left = 0, right = (int) (my_numbers.size() - 1), mid = 0;

    while (left <= right) {
        iteration++;
        mid = (left + right) / 2;
        if (key == my_numbers[mid]) {
            cout << "Binary search found " << my_numbers[mid] << " after " << iteration << " iterations.\n";
            return;
        } else if (key > my_numbers[mid])
            left = mid + 1;
        else
            right = mid - 1;
    }
    cout << "Binary search did not found " << my_numbers[mid] << " after " << iteration << " iterations.\n";

    return;

}