C# Online Compiler | .NET Fiddle

using System;
using System.Diagnostics;
using System.Drawing;
using System.Collections.Generic;
					
public class Program
{
	public static void Main()
	{
		
		Console.WriteLine("Room Generator");
		Random rnd = new Random(777);		
		/*
		for (int i=0; i<50; i++)
		{
			Console.WriteLine(rnd.Next(0, 10));
		}
		*/
		
		generateTree(7777);

	}
	
	public static void generateTree(int seed)
	{
		const int MAX_LEAF_SIZE = 20;
		List<Leaf> leaves = new List<Leaf>();
		
		// Create root
		Leaf root = new Leaf(0,0,40,20, seed);
		leaves.Add(root);
		
		Random rnd = new Random(seed+777);
		
		// Loop through leaves
		while (leaves.Count<30)
		{
			int splitIdx = rnd.Next(leaves.Count);
			Leaf toSplit = leaves[splitIdx];
		    if( toSplit.split() ) { //attempt to split
                leaves.Add( toSplit.leftChild );
                leaves.Add( toSplit.rightChild );
            }
		}
		root.generateRoom();
		
		printDungeons(leaves);
		
	}
	
	public static void printDungeons(List<Leaf> leaves) {
        char[][] lines = new char[40][];
        for( int i = 0; i < 40; i++ ) 
		{
            lines[i] = new char[20];
            for( int j = 0; j < 20; j++ )
                lines[i][j] =  '█';
        }
		
        int dungeonCount = -1;
        foreach( Leaf r in leaves ) 
		{
            Rectangle d = r.room;
            dungeonCount++;
			
            for( int i = 0; i < d.Height; i++ ) 
			{
                for( int j = 0; j < d.Width; j++ )

                    lines[ d.X + i ][ d.Y+ j ] = ' ';
            }
        }
		
        for( int j = 0; j < 20; j++ ) 
		{
			for( int i = 0; i < 40; i++ ) 
			{
				/*
                if( lines[ i ][ j ] == -1 )
                    System.out.print( '.');
                else
                    System.out.print( lines[ i ][ j ] );
				*/
				Console.Write(lines[i][j]);
            }
			Console.Write("\n");
        }
    }
}


public class Leaf
{
	const int MIN_SIZE = 4;
	public int x, y, width, height;
	public Leaf leftChild, rightChild;
	public Rectangle room;
	public List<Rectangle> halls = new List<Rectangle>();
	private Random rnd;

	// Initializer
	public Leaf(int inX, int inY, int inWidth, int inHeight, int seed = 0)
	{
		x = inX;
		y = inY;
		width = inWidth;
		height = inHeight;
		//Console.WriteLine("seed="+seed);
		rnd = new Random(seed);
	}
	
	// Splitter
	public bool split()
	{
		// Begin splitting the leaf into two children
		if (leftChild != null || rightChild != null)
			return false; // Bail out if it is alread splitted.
		
		// Determine direction of split
        // if the width is >25% larger than height, we split vertically
        // if the height is >25% larger than the width, we split horizontally
        // otherwise we split randomly
		bool isSplitX = rnd.Next(2)==1;
		if (width > height && height / width >= 0.05)
			isSplitX = false;
		else if (height > width && width / height >= 0.05)
			isSplitX = true;
			
		// Determine max possible size to split
		int max = (isSplitX?height:width) - MIN_SIZE;
		if (max <= MIN_SIZE)
			return false; // This dimension is too small to split
		
		int splitPos = rnd.Next(MIN_SIZE, max);
		//Console.WriteLine(splitPos);
		
		if (isSplitX)
		{
			leftChild = new Leaf(x, y, width, splitPos, rnd.Next(111));
            rightChild = new Leaf(x, y + splitPos, width, height - splitPos, rnd.Next(222));
		}
		else
		{
			leftChild = new Leaf(x, y, splitPos, height, rnd.Next(333));
            rightChild = new Leaf(x + splitPos, y, width - splitPos, height, rnd.Next(444));
		}
		return true; // We have made this far
	}
	
	// Generate Dungeon
	public void generateRoom()
	{
		if (leftChild != null)  //if current are has child areas, propagate the call
		{
			leftChild.generateRoom();
			rightChild.generateRoom();
		}
		else // if leaf node, create a dungeon within the minimum size constraints
		{
			/*
            int dungeonTop = (height - MIN_SIZE <= 0) ? 0 : rnd.Next( height - MIN_SIZE);
            int dungeonLeft =  (width - MIN_SIZE <= 0) ? 0 : rnd.Next( width - MIN_SIZE);
            int dungeonHeight = Math.Max(rnd.Next( height - dungeonTop ), MIN_SIZE );;
            int dungeonWidth = Math.Max(rnd.Next( width - dungeonLeft ), MIN_SIZE );;
            room = new Rectangle( x+dungeonLeft, y + dungeonTop, dungeonHeight, dungeonWidth);
			*/
			int dungeonTop = 0;
            int dungeonLeft =  0;
            int dungeonHeight = Math.Max(height-1, MIN_SIZE );;
            int dungeonWidth = Math.Max(width-1, MIN_SIZE );;
            room = new Rectangle( x+dungeonLeft, y + dungeonTop, dungeonHeight, dungeonWidth);

		}
	}
}

            room = new Rectangle( x+dungeonLeft, y + dungeonTop, dungeonHeight, dungeonWidth);
 
using System;
using System.Diagnostics;
using System.Drawing;
using System.Collections.Generic;
                    
public class Program
{
    public static void Main()
    {
        
        Console.WriteLine("Room Generator");
        Random rnd = new Random(777);       
        /*
        for (int i=0; i<50; i++)
        {
            Console.WriteLine(rnd.Next(0, 10));
        }
        */
        
        generateTree(7777);
​
    }
    
    public static void generateTree(int seed)