Problems while printing hollow square

February 26, 2022

I am trying to print a hollow square, I wrote the following code:

#include <iostream>
using namespace std;

int main () {
    int heigth;
    cout << "Height: ";
    cin >> heigth;

    int width;
    cout << "Width: ";
    cin >> width;

    for (int i = 1; i <= heigth; i++) {

        for ( int j = 1; j <= width;  j++) {

            if (i == 1 || j == 1 || i == heigth || j == width) {
                cout << " # ";         
            } else {
                cout << " ";
            }

        }

        cout << endl;
    }
    return 0;
}

When I run it with h=5 and w=5, I get the following shape:

 #  #  #  #  # 
 #     # 
 #     # 
 #     # 
 #  #  #  #  #

Instead of the a normal square.
I tried to print the value of j, I discovered that in the middle iterations, it jumps from 1 to 5 directly.
Like this:

 # 1 # 2 # 3 # 4 # 5
 # 1    # 5
 # 1    # 5
 # 1    # 5
 # 1 # 2 # 3 # 4 # 5

The numbers you see are the values of j. Why is this happening?

>Solution :

Your code is perfectly fine and so is the value of j. The only problem is that you’re printing " " while you should be printing " ". This is because " # " has 3 characters, so your space also should be 3 characters long.

Final Code:

#include <iostream>

int main() {
    int heigth;
    std::cout << "Height: ";
    std::cin >> heigth;

    int width;
    std::cout << "Width: ";
    std::cin >> width;

    for (int i = 1; i <= heigth; i++) {

        for (int j = 1; j <= width; j++) {

            if (i == 1 || j == 1 || i == heigth || j == width) {
                std::cout << " # ";
            }
            else {
                std::cout << "   "; // Replaced " " with "   "
            }

        }

        std::cout << std::endl;
    }
    return 0;
}

In the above code I’ve also removed the following line: