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Drawing a Circumference in a 2D Array in C#

In this C# program, we declare a 70x20 two-dimensional array of characters and "draw" a circumference with a radius of 8 inside it. The program calculates the points that make up the circumference using the mathematical formula for a circle and plots them on the 2D array. The program then displays the array with the drawn circumference on the screen. This exercise demonstrates the use of trigonometric functions and array manipulation in C#.



Group

C# Arrays, Structures and Strings

Objective

1. Declare a 70x20 two-dimensional array.
2. Use the mathematical formula to calculate the points on the circumference with radius 8.
3. Convert the angle from degrees to radians.
4. Use `Math.Cos` and `Math.Sin` to calculate the x and y positions of the points on the circumference.
5. Display the 2D array, showing the drawn circumference.

Write a C# program that declares creates a 70x20 two-dimensional array of characters, "draws" a circumference or radius 8 inside it, and displays it on screen.

Example C# Exercise

 Copy C# Code 
using System;

class Program
{
    static void Main()
    {
        // Define a 70x20 two-dimensional array
        char[,] grid = new char[70, 20];

        // Define the center of the circumference
        int xCenter = 35; // Horizontal center of the array (middle)
        int yCenter = 10; // Vertical center of the array (middle)

        // Define the radius of the circumference
        int radius = 8;

        // Initialize the array with empty spaces (' ')
        for (int i = 0; i < 70; i++)
        {
            for (int j = 0; j < 20; j++)
            {
                grid[i, j] = ' '; // Empty space
            }
        }

        // Draw the circumference: 72 points (360 degrees / 5 degrees step)
        for (int angle = 0; angle < 360; angle += 5)
        {
            // Convert angle to radians
            double radians = angle * Math.PI / 180.0;

            // Calculate the x and y coordinates for the circumference
            int x = (int)(xCenter + radius * Math.Cos(radians));
            int y = (int)(yCenter + radius * Math.Sin(radians));

            // Ensure the coordinates are within bounds of the array
            if (x >= 0 && x < 70 && y >= 0 && y < 20)
            {
                grid[x, y] = 'X'; // Mark the point on the grid
            }
        }

        // Display the content of the array
        Console.WriteLine("The grid with a circumference of radius 8:");
        for (int i = 0; i < 20; i++)
        {
            for (int j = 0; j < 70; j++)
            {
                Console.Write(grid[j, i]); // Print each character
            }
            Console.WriteLine(); // New line after each row
        }
    }
}

 Output

The grid with a circumference of radius 8:
                                                                              
                                                                              
                           X                                                    
                        X     X                                                
                      X           X                                          
                     X             X                                         
                      X           X                                          
                        X     X                                                
                           X

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