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Display a Hollow Square with a Symbol in C#

In this C# program, the user will be asked to input a symbol and a width. The program will then use that symbol to create a hollow square with the given width. The outer border of the square will be made using the symbol, while the inner area of the square will remain empty. This is a common pattern-building exercise often used to practice loops and conditional logic.

To achieve this, the program needs to iterate through the rows and columns of the square. The first and last rows will be completely filled with the symbol, while the middle rows will have the symbol only at the borders, leaving spaces in between.

This exercise is not only a good way to learn how to use loops in C#, but also to apply basic conditional logic for controlling where to place the symbols and where to leave the space inside the square.



Group

C# Flow Control Basics

Objective

Write a C# program that asks for a symbol and a width, and displays a hollow square of that width using that symbol for the outer border, as shown in this example:

Enter a symbol: 4
Enter the desired width: 3

444
4 4
444

Example C# Exercise

 Copy C# Code 
using System;

namespace HollowSquare
{
    class Program
    {
        static void Main(string[] args)
        {
            // Prompt the user to enter a symbol
            Console.Write("Enter a symbol: ");
            char symbol = Convert.ToChar(Console.ReadLine()); // Read the symbol input as a character

            // Prompt the user to enter the desired width of the square
            Console.Write("Enter the desired width: ");
            int width = int.Parse(Console.ReadLine()); // Read the width of the square

            // Loop through each row
            for (int i = 0; i < width; i++)
            {
                // Loop through each column in the current row
                for (int j = 0; j < width; j++)
                {
                    // Check if it's the first or last row, or the first or last column in the middle rows
                    if (i == 0 || i == width - 1 || j == 0 || j == width - 1)
                    {
                        Console.Write(symbol); // Print the symbol at the borders
                    }
                    else
                    {
                        Console.Write(" "); // Print a space for the hollow area
                    }
                }

                // Move to the next line after each row
                Console.WriteLine();
            }
        }
    }
}

 Output

//Example 1:
Enter a symbol: 4
Enter the desired width: 3

444
4 4
444

//Example 2:
Enter a symbol: *
Enter the desired width: 5

*****
*   *
*   *
*   *
*****

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More C# Practice Exercises of C# Flow Control Basics

Explore our set of C# Practice Exercises! Specifically designed for beginners, these exercises will help you develop a solid understanding of the basics of C#. From variables and data types to control structures and simple functions, each exercise is crafted to challenge you incrementally as you build confidence in coding in C#.