Help for Connect4 game java.

Question

Hello, I am attending Java in the university, previously worked in C++, for my first work on java to me to make the Game of Connect 4 with GUI, navigating the forums i found a code for this game, well this code has a few problems, first the methods checkDiagonalFromTopLeft or checkDiagonalFromBottomLeft dosnt work, especial checkDiagonalFromBottomLeft, second when the 1st game is played and second game is coming the circle is yellow , taht to be RED NOT YELLOW well I NEED YOUR help guys please help mee
the code please see heckDiagonalFromTopLeft checkDiagonalFromTopLeft
especially heckDiagonalFromTopLeft
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Tallers1
     static class Connect4
          extends JPanel
          private static final int SIZE= 30;
          private static final int GAP= 10;
          private static final int ROWS= 6;
          private static final int COLS= 7;
          private Color mColor;
          private Color[][] mCounters;
          public Connect4()
               reset();
               addMouseListener(new MouseAdapter() {
                    public void mousePressed(MouseEvent e) {
                         hitTest(e.getPoint());
          private void hitTest(Point point) {
int row = Math.min((point.y / (SIZE+GAP)*ROWS) / ROWS, ROWS-1);
int col = Math.min((point.x / (SIZE+GAP)*COLS) / COLS, COLS-1);
               if (mCounters[col][row] == null) {
                    for (row= ROWS-1; row >= 0; row--) {
                         if (mCounters[col][row] == null) {
                              mCounters[col][row]= mColor;
                              repaint();
                              check(col, row);
                              mColor= mColor == Color.RED ?
                                   Color.YELLOW : Color.RED;
                              return;
          private void check(int col, int row)
               if (checkVertical(col) ||
                    checkHorizontal(row) ||
                    checkDiagonalFromTopLeft(col, row) ||
                    checkDiagonalFromBottomLeft(col, row))
                    alert();
          private boolean checkDiagonalFromTopLeft(int col, int row)
               if (col >= row) {
                    col= col-row;
                    row= 0;
               else {
                    row= row-col;
                    col= 0;
               for (int cnt= 0; row < ROWS && col < COLS; row++, col++) {
                    if (mCounters[col][row] == mColor) {
                         if (++cnt >= 4)
                              return true;
                    else
                         cnt= 0;
               return false;
          private boolean checkDiagonalFromBottomLeft(int col, int row) {
if(row >= ROWS-1) {
// do nowt and move on to the checking.
else {
int delta= Math.min(3, col);
col= Math.max(0, col-delta);
row= Math.min(ROWS-1, row+delta);
for (int tally= 0; row >= 0 && col < COLS; row--, col++) {
if (mCounters[col][row] == mColor) {
if (++tally >= 4)
return true;
} else
tally= 0;
return false;
          private boolean checkVertical(int col)
               for (int cnt= 0, row= 0; row < ROWS; row++) {
                    if (mCounters[col][row] == mColor) {
                         if (++cnt >= 4)
                              return true;
                    else
                         cnt= 0;
               return false;
          private boolean checkHorizontal(int row)
               for (int cnt= 0, col= 0; col < COLS; col++) {
                    if (mCounters[col][row] == mColor) {
                         if (++cnt >= 4)
                              return true;
                    else
                         cnt= 0;
               return false;
          private void alert()
               int option= JOptionPane.showConfirmDialog(this,
                    (mColor == Color.RED ? "Red" : "Yellow") +
                         " wins! Want to go again?",
                    "Game Over",
                    JOptionPane.YES_NO_OPTION);
               if (option == JOptionPane.YES_OPTION)
                    reset();
               else
                    System.exit(0);
          private void reset()
               mCounters= new Color[COLS][ROWS];
               mColor= Color.RED;
               repaint();
          public void paint(Graphics g)
               g.setColor(Color.BLUE);
               g.fillRect(0, 0, getSize().width, getSize().height);
               for (int col= 0; col< COLS; col++) {
                    for (int row= 0; row< ROWS; row++) {
                         g.setColor(mCounters[col][row] == null ?
                              Color.WHITE : mCounters[col][row]);
                         g.fillOval(
                              GAP+((GAP+SIZE)*col),
                              GAP+((GAP+SIZE)*row),
                              SIZE, SIZE);
          public Dimension getPreferredSize()
               return new Dimension(
                    ((SIZE+GAP)*COLS) +GAP,
                    ((SIZE+GAP)*ROWS) +GAP);
     public static void main(String[] argv)
          JFrame frame= new JFrame();
          frame.getContentPane().add(new Connect4());
          frame.pack();
          frame.setResizable(false);
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.setVisible(true);
}

Answer 1

hi, 2) the GUI is from the forums the algorhytm is made by me, so i need to now wy the diagonal dostn Work ON GUI please, sorry my bad english i m from argentina
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Tallers1
static class Connect4
extends JPanel
private static final int SIZE= 30;
private static final int GAP= 10;
private static final int ROWS= 6;
private static final int COLS= 7;
private Color mColor;
private Color[][] mCounters;
public Connect4()
reset();
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
hitTest(e.getPoint());
private void hitTest(Point point) {
int row = Math.min((point.y / (SIZE+GAP)*ROWS) / ROWS, ROWS-1);
int col = Math.min((point.x / (SIZE+GAP)*COLS) / COLS, COLS-1);
if (mCounters[col][row] == null) {
for (row= ROWS-1; row >= 0; row--) {
if (mCounters[col][row] == null) {
mCounters[col][row]= mColor;
repaint();
check(col, row);
mColor= mColor == Color.RED ?
Color.YELLOW : Color.RED;
return;
private void check(int col, int row)
if (checkVertical(col) ||
checkHorizontal(row) ||
checkDiagonalFromTopLeft(col, row) ||
checkDiagonalFromBottomLeft(col, row))
alert();
private boolean checkDiagonalFromTopLeft(int col, int row)
if (col >= row) {
col= col-row;
row= 0;
else {
row= row-col;
col= 0;
for (int cnt= 0; row < ROWS && col < COLS; row++, col++) {
if (mCounters[col][row] == mColor) {
if (++cnt >= 4)
return true;
else
cnt= 0;
return false;
private boolean checkDiagonalFromBottomLeft(int col, int row) {
if(row >= ROWS-1) {
// do nowt and move on to the checking.
else {
int delta= Math.min(3, col);
col= Math.max(0, col-delta);
row= Math.min(ROWS-1, row+delta);
for (int tally= 0; row >= 0 && col < COLS; row--, col++) {
if (mCounters[col][row] == mColor) {
if (++tally >= 4)
return true;
} else
tally= 0;
return false;
private boolean checkVertical(int col)
for (int cnt= 0, row= 0; row < ROWS; row++) {
if (mCounters[col][row] == mColor) {
if (++cnt >= 4)
return true;
else
cnt= 0;
return false;
private boolean checkHorizontal(int row)
for (int cnt= 0, col= 0; col < COLS; col++) {
if (mCounters[col][row] == mColor) {
if (++cnt >= 4)
return true;
else
cnt= 0;
return false;
private void alert()
int option= JOptionPane.showConfirmDialog(this,
(mColor == Color.RED ? "Red" : "Yellow") +
" wins! Want to go again?",
"Game Over",
JOptionPane.YES_NO_OPTION);
if (option == JOptionPane.YES_OPTION)
reset();
else
System.exit(0);
private void reset()
mCounters= new Color[COLS][ROWS];
mColor= Color.RED;
repaint();
public void paint(Graphics g)
g.setColor(Color.BLUE);
g.fillRect(0, 0, getSize().width, getSize().height);
for (int col= 0; col< COLS; col++) {
for (int row= 0; row< ROWS; row++) {
g.setColor(mCounters[col][row] == null ?
Color.WHITE : mCounters[col][row]);
g.fillOval(
GAP+((GAP+SIZE)*col),
GAP+((GAP+SIZE)*row),
SIZE, SIZE);
public Dimension getPreferredSize()
return new Dimension(
((SIZE+GAP)*COLS) +GAP,
((SIZE+GAP)*ROWS) +GAP);
public static void main(String[] argv)
JFrame frame= new JFrame();
frame.getContentPane().add(new Connect4());
frame.pack();
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}