How can I fix a code that crash every time I try to compile (chess game in c++)?

Question

I'm trying to make a chess game in C++ and I already have the chessboard and the chess Pieces. When I try to compile the code it does work and there a window that pop in my screen that shows the chessboard and the pieces. However, when I try to click a piece the whole code just crash without giving me any error or warning. Also, my game is only supported on Qt creator. I really need help to stop my code crashing thank you. P.S: Sorry if there any grammar mistake it's because English is not my first language.

//this is the code for the mainwindow

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QPushButton>
#include <QGridLayout>
#include <QMouseEvent>
#include <QPoint>



QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class Pieces {
    public:
             Pieces(int x, int y,char color, char pieces) : x(x), y(y), color(color), pieces(pieces) {};

    char getColor() const{
    return color;
};

int getX(){
    return x;
};

int getY(){
    return y;
};
int setX(int x) {
    return x;
};
int setY(int y) {
    return y;
};
char getPieces() const{
    return pieces;
};

private:
int x;
int y;
char color;
char pieces;
};






class MainWindow : public QMainWindow

{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
    Pieces* pieces;
    void chessboard(QPushButton* buttons[8][8], QWidget* parentWidget);
    void startingPoint(char team, QPushButton* buttons[8][8]);
    bool isKingMoveValid(int newRow, int newCol);
    bool isMoveBlocked(int newRow, int newCol);
    void onButtonClicked(int row, int col);
    void setupBoard();
    void moveKing(int dx, int dy);






private:
    Ui::MainWindow *ui;
    QPushButton* buttons[8][8];
    int selectedRow = -1;
    int selectedCol = -1;
    int col_init = -1;
    int row_init = -1;

private slots:

    void mousePressEvent(QMouseEvent* event);

};



#endif // MAINWINDOW_H

// this is the code for the main

#include <QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MainWindow window;
    window.show();
    return app.exec();
}

// this is the code for the mainwindow.cpp

#include "mainwindow.h"
#include "./ui_mainwindow.h"
#include <iostream>
#include <QMouseEvent>
#include <QPushButton>
using namespace std;





MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    chessboard(buttons, ui->centralwidget);
    startingPoint('B', buttons);
    startingPoint('W', buttons);
    for (int row = 0; row < 8; ++row) {
        for (int col = 0; col < 8; ++col) {
            connect(buttons[row][col], &QPushButton::clicked, this, [this, row, col]() {
                onButtonClicked(row, col);
            });
        }
    }
}

void MainWindow::chessboard(QPushButton* buttons[8][8], QWidget* parentWidget) {
    QGridLayout* gridLayout = new QGridLayout(parentWidget);
    for (int row = 0; row < 8; ++row) {
        for (int col = 0; col < 8; ++col) {
            buttons[row][col] = new QPushButton(parentWidget);
            buttons[row][col]->setFixedSize(110, 110);
            if ((row + col) % 2 == 0) {
                buttons[row][col]->setStyleSheet("background-color: white");
            } else {
                buttons[row][col]->setStyleSheet("background-color: pink");
            }
            gridLayout->addWidget(buttons[row][col], row, col);
        }
    }

}

void MainWindow::startingPoint(char team, QPushButton* buttons[8][8]) {
    int rowRook, rowPawn;
    if (team == 'W') {
        rowRook = 0;
        rowPawn = 1;
    }
    else {
        rowRook = 7;
        rowPawn = 6;
    }

    Pieces* rook = new Pieces(rowRook, 0, team, 'T');
    QPushButton* rookButton = buttons[rook->getX()][rook->getY()];
    rookButton->setText(QString(QChar(0x2656)));
    rookButton->setFont(QFont("Arial", 50));

    Pieces* knight = new Pieces(rowRook, 1, team, 'C');
    QPushButton* knightButton = buttons[knight->getX()][knight->getY()];
    knightButton->setText(QString(QChar(0x2658)));
    knightButton->setFont(QFont("Arial", 50));

    Pieces* bishop = new Pieces(rowRook, 2, team, 'F');
    QPushButton* bishopButton = buttons[bishop->getX()][bishop->getY()];
    bishopButton->setText(QString(QChar(0x2657)));
    bishopButton->setFont(QFont("Arial", 50));

    Pieces* queen = new Pieces(rowRook, 3, team, 'D');
    QPushButton* queenButton = buttons[queen->getX()][queen->getY()];
    queenButton->setText(QString(QChar(0x2655)));
    queenButton->setFont(QFont("Arial", 50));

    Pieces* king = new Pieces(rowRook, 4, team, 'R');
    QPushButton* kingButton = buttons[king->getX()][king->getY()];
    kingButton->setText(QString(QChar(0x2654)));
    kingButton->setFont(QFont("Arial", 50));

    Pieces* bishop2 = new Pieces(rowRook, 5, team, 'F');
    QPushButton* bishop2Button = buttons[bishop2->getX()][bishop2->getY()];
    bishop2Button->setText(QString(QChar(0x2657)));
    bishop2Button->setFont(QFont("Arial", 50));

    Pieces* knight2 = new Pieces(rowRook, 6, team, 'C');
    QPushButton* knight2Button = buttons[knight2->getX()][knight2->getY()];
    knight2Button->setText(QString(QChar(0x2658)));
    knight2Button->setFont(QFont("Arial", 50));

    Pieces* rook2 = new Pieces(rowRook, 7, team, 'T');
    QPushButton* rook2Button = buttons[rook2->getX()][rook2->getY()];
    rook2Button->setText(QString(QChar(0x2656)));
    rook2Button->setFont(QFont("Arial", 50));

    for (int i = 0; i < 8; i++) {
        Pieces* pawn = new Pieces(rowPawn, i, team, 'P');
        QPushButton* pawnButton = buttons[pawn->getX()][pawn->getY()];
        pawnButton->setText(QString(QChar(0x265F)));
        pawnButton->setFont(QFont("Arial", 50));
    }
}

void MainWindow::onButtonClicked(int row, int col) {
    if (pieces->getX() == row && pieces->getY() == col) {
        buttons[row][col]->setStyleSheet("background-color: green");
        col_init = col;
        row_init = row;
    } else if (col_init != -1 && row_init != -1) {
        if ((abs(row_init - row) <= 1) && (abs(col_init - col) <= 1)) {
            buttons[row][col]->setText(QString(pieces->getPieces()));
            buttons[row][col]->setStyleSheet("color: red; font-size: 100px;");
            buttons[row_init][col_init]->setText("");
            pieces->setX(row);
            pieces->setY(col);
        }
        col_init = -1;
        row_init = -1;
    }
}

void MainWindow::mousePressEvent(QMouseEvent* event) {
    int row = -1, col = -1;
    for (int i = 0; i < 8; i++) {
        for (int j = 0; j < 8; j++) {
            if (event->button() == Qt::LeftButton && event->pos() == buttons[i][j]->pos()) {
                row = i;
                col = j;
                break;
            }
        }
        if (row != -1 && col != -1) {
            break;
        }
    }
    onButtonClicked(row,col);
}


MainWindow::~MainWindow() {
    delete ui;
};