Question

[C++] Write an interactive program to help you count all of the boxes in a room. The program should begin by asking something like

How many unnumbered boxes can you see? Then the program will have you number those boxes from 1 to m, where m is your answer. But, remember that each box might have smaller boxes inside, so once the program knows you can see m boxes, it should ask you to open box number 1 and take out any box- es you find, numbering those boxes 1.1, 1.2, and so on. It will also ask you to open box number 2 and take out any boxes you find there, numbering those boxes 2.1, 2.2, and so on. This continues for box 3, 4, up to m. And, of course, each time you number a box 1.1 or 3.8 or something similar, that box might have more boxes inside. Boxes that reside inside of 3.8 would be numbered 3.8.1, 3.8.2, and so on. At the end, the program should print a single number tell- ing you the total number of boxes in the room.

Answer 1

This problem can be solved using a recursive approach.The base case here will be to open a box which does not contain any other box. So the approach is to recursively iterate each box until we find an empty box. While iterating keep track of the count and return it to the previous function call. I have shared the code below -

#include <iostream>
#include <string>

using namespace std;

// child variable is the box to open
// parent variable keeps track of the previous boxes opened
int open(string child, string parent)
{
    int count;
    if (child == "")
    {
        cout << "How many un-numbered boxes do you see in the room? ";
    }
    else
    {
        cout << "Open box " << (parent + child).substr(1) << " How many do you see? " << endl;
    }
    cin >> count;
    // base case
    // if there are no more boxes then return 0
    if (count == 0)
    {
        return 0;
    }
    else
    {
        // recursive step
        // for each choice of boxes
        int sum = 0;
        for (int i = 1; i <= count; i++)
        {
            // explore the boxes inside
            sum += open(to_string(i), parent + child + ".") + 1;
        }
        // return the sum
        return sum;
    }
}

int main()
{
    int total = 0;
    total = open("", "");
    cout << "Total number of boxes: " << total << endl;
    return 0;
}

I am also sharing the screenshot of the code for readability and the screenshot of the code execution.