用qt如何设计计算器代码

设计计算器代码可以分为以下几个步骤：

1. 设计UI界面：可以使用Qt Designer来设计计算器的UI界面。在UI界面中添加按钮、文本框等控件，并设置好它们的属性和布局。

2. 连接信号槽：在UI界面中的按钮被点击时，需要触发相应的计算操作。因此需要将按钮的clicked信号与相应的槽函数连接起来。

3. 编写计算函数：根据计算器的功能，编写相应的计算函数。例如，加、减、乘、除等操作。

4. 实现计算逻辑：在槽函数中调用计算函数，获取用户输入的数字和操作符，并计算得出结果。

5. 在UI界面中显示结果：将计算结果显示在UI界面中的文本框中。

下面是一个简单的计算器示例代码：

#include <QApplication>
#include <QWidget>
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QPushButton>
#include <QLineEdit>

class Calculator : public QWidget
{
public:
    Calculator(QWidget *parent = nullptr);

private slots:
    void onButtonClicked();

private:
    QLineEdit *m_display;
    QPushButton *m_btn0;
    QPushButton *m_btn1;
    QPushButton *m_btn2;
    QPushButton *m_btn3;
    QPushButton *m_btn4;
    QPushButton *m_btn5;
    QPushButton *m_btn6;
    QPushButton *m_btn7;
    QPushButton *m_btn8;
    QPushButton *m_btn9;
    QPushButton *m_btnAdd;
    QPushButton *m_btnSub;
    QPushButton *m_btnMul;
    QPushButton *m_btnDiv;
    QPushButton *m_btnEqual;
};

Calculator::Calculator(QWidget *parent)
    : QWidget(parent),
      m_display(new QLineEdit),
      m_btn0(new QPushButton("0")),
      m_btn1(new QPushButton("1")),
      m_btn2(new QPushButton("2")),
      m_btn3(new QPushButton("3")),
      m_btn4(new QPushButton("4")),
      m_btn5(new QPushButton("5")),
      m_btn6(new QPushButton("6")),
      m_btn7(new QPushButton("7")),
      m_btn8(new QPushButton("8")),
      m_btn9(new QPushButton("9")),
      m_btnAdd(new QPushButton("+")),
      m_btnSub(new QPushButton("-")),
      m_btnMul(new QPushButton("*")),
      m_btnDiv(new QPushButton("/")),
      m_btnEqual(new QPushButton("="))
{
    m_display->setReadOnly(true);

    QHBoxLayout *hLayout1 = new QHBoxLayout;
    hLayout1->addWidget(m_btn0);
    hLayout1->addWidget(m_btn1);
    hLayout1->addWidget(m_btn2);
    hLayout1->addWidget(m_btn3);

    QHBoxLayout *hLayout2 = new QHBoxLayout;
    hLayout2->addWidget(m_btn4);
    hLayout2->addWidget(m_btn5);
    hLayout2->addWidget(m_btn6);
    hLayout2->addWidget(m_btn7);

    QHBoxLayout *hLayout3 = new QHBoxLayout;
    hLayout3->addWidget(m_btn8);
    hLayout3->addWidget(m_btn9);
    hLayout3->addWidget(m_btnAdd);
    hLayout3->addWidget(m_btnSub);

    QHBoxLayout *hLayout4 = new QHBoxLayout;
    hLayout4->addWidget(m_btnMul);
    hLayout4->addWidget(m_btnDiv);
    hLayout4->addWidget(m_btnEqual);

    QVBoxLayout *vLayout = new QVBoxLayout;
    vLayout->addWidget(m_display);
    vLayout->addLayout(hLayout1);
    vLayout->addLayout(hLayout2);
    vLayout->addLayout(hLayout3);
    vLayout->addLayout(hLayout4);

    setLayout(vLayout);

    connect(m_btn0, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn1, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn2, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn3, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn4, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn5, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn6, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn7, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn8, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btn9, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btnAdd, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btnSub, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btnMul, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btnDiv, &QPushButton::clicked, this, &Calculator::onButtonClicked);
    connect(m_btnEqual, &QPushButton::clicked, this, &Calculator::onButtonClicked);
}

void Calculator::onButtonClicked()
{
    QPushButton *btn = qobject_cast<QPushButton *>(sender());
    if (!btn)
        return;

    QString text = btn->text();
    QString displayText = m_display->text();

    if (text == "+" || text == "-" || text == "*" || text == "/")
    {
        // 计算当前表达式的值
        double leftOperand = displayText.toDouble();
        double rightOperand = m_display->property("rightOperand").toDouble();
        QString lastOperator = m_display->property("lastOperator").toString();

        double result = 0.0;
        if (lastOperator == "+")
            result = leftOperand + rightOperand;
        else if (lastOperator == "-")
            result = leftOperand - rightOperand;
        else if (lastOperator == "*")
            result = leftOperand * rightOperand;
        else if (lastOperator == "/")
            result = leftOperand / rightOperand;

        m_display->setText(QString::number(result));
        m_display->setProperty("lastOperator", text);
        m_display->setProperty("rightOperand", displayText);
    }
    else if (text == "=")
    {
        // 计算最终结果
        double leftOperand = displayText.toDouble();
        double rightOperand = m_display->property("rightOperand").toDouble();
        QString lastOperator = m_display->property("lastOperator").toString();

        double result = 0.0;
        if (lastOperator == "+")
            result = leftOperand + rightOperand;
        else if (lastOperator == "-")
            result = leftOperand - rightOperand;
        else if (lastOperator == "*")
            result = leftOperand * rightOperand;
        else if (lastOperator == "/")
            result = leftOperand / rightOperand;

        m_display->setText(QString::number(result));
    }
    else
    {
        // 更新显示内容
        displayText += text;
        m_display->setText(displayText);
    }
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    Calculator calculator;
    calculator.show();

    return app.exec();
}

这个示例代码中，我们使用QLineEdit来显示计算器的输入和输出，使用QPushButton来实现数字和操作符的按钮。在槽函数onButtonClicked()中，我们根据用户的输入进行相应的计算并在QLineEdit中显示结果。