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Randomly Placing Characters in a 2D Array in C#

This C# program declares a 70x20 two-dimensional array of characters and randomly places 80 "X" characters in various positions within the array. After the random placement, it displays the contents of the array on the screen. This exercise demonstrates how to work with 2D arrays, generate random numbers, and manipulate array elements in C#.



Group

C# Arrays, Structures and Strings

Objective

1. Declare a 2D array with dimensions 70x20.
2. Randomly place 80 "X" characters in different positions in the array.
3. Display the entire content of the array, showing "X" where placed and spaces where no "X" was placed.

Write a C# program that declares a 70x20 two-dimensional array of characters, "draws" 80 letters (X, for example) in random positions and displays the content of the array 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];

        // Create a Random object to generate random numbers
        Random rand = new Random();

        // 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
            }
        }

        // Place 80 'X' characters in random positions
        int placedCount = 0;
        while (placedCount < 80)
        {
            int x = rand.Next(0, 70); // Random X position (0 to 69)
            int y = rand.Next(0, 20); // Random Y position (0 to 19)

            // Place 'X' only if the position is currently empty
            if (grid[x, y] == ' ')
            {
                grid[x, y] = 'X'; // Place 'X'
                placedCount++;     // Increment count of placed 'X'
            }
        }

        // Display the content of the array
        Console.WriteLine("The grid with 80 'X' characters:");
        for (int i = 0; i < 20; i++)
        {
            for (int j = 0; j < 70; j++)
            {
                Console.Write(grid[j, i]);
            }
            Console.WriteLine(); // New line after each row
        }
    }
}

 Output

The grid with 80 'X' characters:
XX   XX X  X           X
   X      X     X     X
 X    X X  X     X X  
 X X    X   X  X      
  X    X     X       
 X  X        X    X   
X X   X    X    X    
X   X         X   X  
   X X   X    X  X   
X    X   X  X   X    
       X   X     X  
    X   X  X    X    
  X    X   X       
   X      X X  X   
     X     X   X   
X   X   X   X X    
X  X   X X X X    
X      X X     X

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