connect4

commit 599029950fec9bc8f199875cd9d2d701639144f6
parent 45c7a3eb49175a5f88c87b7bd5599c369c68c0a7
Author: sej <sej@sejdt.localhost>
Date:   Tue,  1 Oct 2024 00:47:06 +0200

Implemented board class

Diffstat:
M
Board.cs
 | 
143
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
M
Connect4.cs
 | 
4
++--

2 files changed, 138 insertions(+), 9 deletions(-)
diff --git a/Board.cs b/Board.cs
@@ -3,15 +3,144 @@ using System.Collections.Generic;
 using System.Linq;
 
 public class Board {
-    int n;
-    int m;
-    char[,] board;
+    private int _n; // number of columns
+    private int _m; // number of rows
+    private Cell[,] _board;
+    private int[] _height;
+    private Cell _next;
+    private Status _status;
 
-    public Board() {
-        
+    public enum Cell {
+        Free = 0, // make sure free is the default value
+        PlayerX,
+        PlayerO,
     }
 
-    public void Hello() {
-        Console.WriteLine( "Hello from Board" );
+    public enum Status {
+        InProgress,
+        PlayerXWon,
+        PlayerOWon,
+        Draw,
+    }
+
+    /*
+     * Constructs a board with m rows and n columns.
+     */
+    public Board( int n, int m ) {
+        _m = m;
+        _n = n;
+        _board = new Cell[ m, n ];
+        _height = new int[ n ];
+        _next = Cell.PlayerX; // player X starts
+        _status = Status.InProgress;
+    }
+
+    /*
+     * Determines if it is legal to play a piece in the given column
+     */
+    public bool IsLegal( int column ) {
+        return _height[ column ] < _m;
+    }
+
+    /*
+     * assumes play is legal
+     */
+    public void Play( int column ) {
+        _board[ _m - _height[ column ] - 1, column ] = _next;
+        _height[ column ] ++;
+        _next = ( _next == Cell.PlayerX ) ? Cell.PlayerO : Cell.PlayerX;
+        ComputeStatus();
+    }
+
+    /*
+     * returns whos turn it is
+     */
+    public Cell getNext() {
+        return _next;
+    }
+
+    /*
+     * Pretty prints the board
+     */
+    public void PrettyPrint() {
+        char[] prettyChar = { '.', 'X', 'O' };
+        for ( int j = 0; j < _m; j++ ) {
+            for ( int i = 0; i < _n; i++ ) {
+                Console.Write( prettyChar[ (int) _board[ j, i ] ] );
+            }
+            Console.Write( "\n" );
+        }
+        Console.WriteLine( _status );
+    }
+
+    /*
+     * Returns a list of all legal moves on this board 
+     */
+    public List< int > LegalMoves() {
+        List< int > legalMoves = new List< int >();
+        for ( int i = 0; i < _m; i ++ ) {
+            if ( IsLegal( i ) ) {
+                legalMoves.Add( i );
+            }
+        }
+        return legalMoves;
+    }
+
+    /*
+     * Computes the status of this board, ie. has someone won by obtaining four in a row.
+     */
+    public Status ComputeStatus() {
+        foreach ( Cell player in new Cell[] { Cell.PlayerX, Cell.PlayerO } ) {
+            // Check for vertical four in a row
+            ComputeStatus(
+                ( j, i, k ) => _board[ j + k, i ],
+                j => j < _m - 3,
+                _ => true,
+                player
+            );
+            // Check for horizontal four in a row
+            ComputeStatus(
+                ( j, i, k ) => _board[ j, i + k ],
+                _ => true,
+                i => i < _n - 3,
+                player
+            );
+            // Check for diagonal four in a row
+            ComputeStatus(
+                ( j, i, k ) => _board[ j + k, i + k ],
+                j => j < _m - 3,
+                i => i < _n - 3,
+                player
+            );
+            // Check for alternate diagonal four in a row
+            ComputeStatus(
+                ( j, i, k ) => _board[ j - k, i + k ],
+                j => j > 3,
+                i => i < _n - 3,
+                player
+            );
+        }
+        return _status;
+    }
+
+    /*
+     * Helper method
+     */
+    private void ComputeStatus( Func< int, int, int, Cell > f, Predicate< int > YOkay, Predicate< int > XOkay, Cell player ) {
+        int j = 0;
+        while ( _status == Status.InProgress && j < _m ) {
+            int i = 0;
+            while ( _status == Status.InProgress && i < _n ) {
+                int k = 0;
+                while ( XOkay( i ) && YOkay( j ) && k < 4 && f( j, i, k ) == player ) {
+                    k ++;
+                }
+                if ( k == 4 ) {
+                    _status = player == Cell.PlayerX ? Status.PlayerXWon : Status.PlayerOWon;
+                }
+                i ++;
+            }
+            j ++;
+        }
     }
 }
diff --git a/Connect4.cs b/Connect4.cs
@@ -2,7 +2,7 @@ using System;
 
 public class Connect4 {
     public static void Main( String[] args ) {
-        Board board = new Board();
-        board.Hello();
+        Board board = new Board( 7, 6 );
+        board.PrettyPrint();
     }
 }