简易计算器，窗口界面自由发挥，编程实现两个整数的加、减、乘、除操作。要求如下: 首先进行操作数文本框检验，检验输入数据是否为纯数字； 通过分别单击加、减、乘、除按钮，对操作数1与操作数2进行相应加、减、乘、除操作，并且将其结果写入操作3文本框。

好的，以下是一个简易计算器窗口界面的 C++ 代码示例：

#include <iostream>
#include <QtWidgets/QApplication>
#include <QtWidgets/QWidget>
#include <QtWidgets/QVBoxLayout>
#include <QtWidgets/QHBoxLayout>
#include <QtWidgets/QLabel>
#include <QtWidgets/QLineEdit>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QMessageBox>
using namespace std;

class Calculator : public QWidget {
    Q_OBJECT
public:
    Calculator(QWidget *parent = 0) : QWidget(parent) {
        // 操作数1和操作数2的文本框
        QLineEdit *operand1Edit = new QLineEdit;
        QLineEdit *operand2Edit = new QLineEdit;
        operand1Edit->setValidator(new QIntValidator(this));
        operand2Edit->setValidator(new QIntValidator(this));
        // 操作符和结果的文本标签
        QLabel *operatorLabel = new QLabel("+");
        QLabel *resultLabel = new QLabel("结果：0");
        // 加、减、乘、除按钮
        QPushButton *addButton = new QPushButton("+");
        QPushButton *subButton = new QPushButton("-");
        QPushButton *mulButton = new QPushButton("*");
        QPushButton *divButton = new QPushButton("/");
        // 布局
        QVBoxLayout *leftLayout = new QVBoxLayout;
        QVBoxLayout *rightLayout = new QVBoxLayout;
        QHBoxLayout *operatorLayout = new QHBoxLayout;
        QHBoxLayout *resultLayout = new QHBoxLayout;
        QHBoxLayout *buttonLayout = new QHBoxLayout;
        leftLayout->addWidget(new QLabel("操作数1"));
        leftLayout->addWidget(new QLabel("操作数2"));
        leftLayout->addStretch();
        leftLayout->addWidget(new QLabel("操作符"));
        leftLayout->addWidget(new QLabel("结果"));
        rightLayout->addWidget(operand1Edit);
        rightLayout->addWidget(operand2Edit);
        rightLayout->addStretch();
        operatorLayout->addWidget(operatorLabel);
        operatorLayout->addStretch();
        resultLayout->addWidget(resultLabel);
        resultLayout->addStretch();
        buttonLayout->addWidget(addButton);
        buttonLayout->addWidget(subButton);
        buttonLayout->addWidget(mulButton);
        buttonLayout->addWidget(divButton);
        // 连接信号和槽函数
        connect(addButton, SIGNAL(clicked()), this, SLOT(add()));
        connect(subButton, SIGNAL(clicked()), this, SLOT(sub()));
        connect(mulButton, SIGNAL(clicked()), this, SLOT(mul()));
        connect(divButton, SIGNAL(clicked()), this, SLOT(div()));
        connect(operand1Edit, SIGNAL(textChanged(const QString&)), this, SLOT(checkInput()));
        connect(operand2Edit, SIGNAL(textChanged(const QString&)), this, SLOT(checkInput()));
        // 设置布局
        QHBoxLayout *mainLayout = new QHBoxLayout;
        mainLayout->addLayout(leftLayout);
        mainLayout->addLayout(rightLayout);
        mainLayout->addLayout(operatorLayout);
        mainLayout->addLayout(resultLayout);
        mainLayout->addLayout(buttonLayout);
        setLayout(mainLayout);
    }
private slots:
    void checkInput() {
        QLineEdit *operand1Edit = qobject_cast<QLineEdit*>(sender());
        if (operand1Edit) {
            if (operand1Edit->text().isEmpty()) {
                return;
            }
            bool ok;
            operand1Edit->text().toInt(&ok);
            if (!ok) {
                QMessageBox::warning(this, "错误", "请输入纯数字");
                operand1Edit->setText("");
            }
        }
        QLineEdit *operand2Edit = qobject_cast<QLineEdit*>(sender());
        if (operand2Edit) {
            if (operand2Edit->text().isEmpty()) {
                return;
            }
            bool ok;
            operand2Edit->text().toInt(&ok);
            if (!ok) {
                QMessageBox::warning(this, "错误", "请输入纯数字");
                operand2Edit->setText("");
            }
        }
    }
    void add() {
        QLineEdit *operand1Edit = findChild<QLineEdit*>("");
        QLineEdit *operand2Edit = findChild<QLineEdit*>("");
        QLabel *operatorLabel = findChild<QLabel*>("");
        QLabel *resultLabel = findChild<QLabel*>("");
        int operand1 = operand1Edit->text().toInt();
        int operand2 = operand2Edit->text().toInt();
        int result = operand1 + operand2;
        operatorLabel->setText("+");
        resultLabel->setText("结果：" + QString::number(result));
    }
    void sub() {
        QLineEdit *operand1Edit = findChild<QLineEdit*>("");
        QLineEdit *operand2Edit = findChild<QLineEdit*>("");
        QLabel *operatorLabel = findChild<QLabel*>("");
        QLabel *resultLabel = findChild<QLabel*>("");
        int operand1 = operand1Edit->text().toInt();
        int operand2 = operand2Edit->text().toInt();
        int result = operand1 - operand2;
        operatorLabel->setText("-");
        resultLabel->setText("结果：" + QString::number(result));
    }
    void mul() {
        QLineEdit *operand1Edit = findChild<QLineEdit*>("");
        QLineEdit *operand2Edit = findChild<QLineEdit*>("");
        QLabel *operatorLabel = findChild<QLabel*>("");
        QLabel *resultLabel = findChild<QLabel*>("");
        int operand1 = operand1Edit->text().toInt();
        int operand2 = operand2Edit->text().toInt();
        int result = operand1 * operand2;
        operatorLabel->setText("*");
        resultLabel->setText("结果：" + QString::number(result));
    }
    void div() {
        QLineEdit *operand1Edit = findChild<QLineEdit*>("");
        QLineEdit *operand2Edit = findChild<QLineEdit*>("");
        QLabel *operatorLabel = findChild<QLabel*>("");
        QLabel *resultLabel = findChild<QLabel*>("");
        int operand1 = operand1Edit->text().toInt();
        int operand2 = operand2Edit->text().toInt();
        if (operand2 == 0) {
            QMessageBox::warning(this, "错误", "除数不能为0");
            return;
        }
        int result = operand1 / operand2;
        operatorLabel->setText("/");
        resultLabel->setText("结果：" + QString::number(result));
    }
};

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

该程序使用了 Qt 框架，实现了一个带有文本框、标签和按钮的窗口界面，可以进行加、减、乘、除操作。其中，checkInput() 槽函数用于检验操作数文本框中输入的内容是否为纯数字，如果不是则弹出错误提示框；add()、sub()、mul() 和 div() 槽函数分别用于进行加、减、乘、除操作，并将结果写入结果文本标签中。