qt实现计算器

要实现一个基本的计算器，你可以使用Qt的QLineEdit和QPushButton类来创建用户界面。下面是一个简单的实现方法：

1. 创建一个Qt项目并打开mainwindow.ui文件。
2. 拖动QLineEdit和QPushButton控件到窗口中，并按照你想要的方式布局。
3. 给每个QPushButton控件添加一个槽函数，当用户单击按钮时会触发该函数。
4. 在每个槽函数中，你需要根据用户单击的按钮来执行相应的操作。例如，如果用户单击了数字按钮，你需要将该数字添加到QLineEdit控件中；如果用户单击了运算符按钮，你需要执行相应的计算操作并将结果显示在QLineEdit控件中。

下面是一个简单的示例代码，可以帮助你开始：

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 为每个按钮添加槽函数
    connect(ui->pushButton_0, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_1, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_2, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_3, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_4, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_5, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_6, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_7, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_8, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_9, SIGNAL(clicked()), this, SLOT(digit_pressed()));
    connect(ui->pushButton_add, SIGNAL(clicked()), this, SLOT(operator_pressed()));
    connect(ui->pushButton_subtract, SIGNAL(clicked()), this, SLOT(operator_pressed()));
    connect(ui->pushButton_multiply, SIGNAL(clicked()), this, SLOT(operator_pressed()));
    connect(ui->pushButton_divide, SIGNAL(clicked()), this, SLOT(operator_pressed()));
    connect(ui->pushButton_equal, SIGNAL(clicked()), this, SLOT(equal_pressed()));
    connect(ui->pushButton_clear, SIGNAL(clicked()), this, SLOT(clear_pressed()));

    // 初始化变量
    m_value = 0.0;
    m_operator = "";
    m_waiting_for_second_operand = false;
}

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

// 数字按钮槽函数
void MainWindow::digit_pressed()
{
    QPushButton* button = (QPushButton*)sender();
    QString digit = button->text();
    QString display_text = ui->lineEdit->text();

    if (m_waiting_for_second_operand)
    {
        ui->lineEdit->setText(digit);
        m_waiting_for_second_operand = false;
    }
    else
    {
        ui->lineEdit->setText(display_text + digit);
    }
}

// 运算符按钮槽函数
void MainWindow::operator_pressed()
{
    QPushButton* button = (QPushButton*)sender();
    QString op = button->text();
    double operand = ui->lineEdit->text().toDouble();

    if (m_operator == "")
    {
        m_value = operand;
    }
    else if (m_operator == "+")
    {
        m_value += operand;
    }
    else if (m_operator == "-")
    {
        m_value -= operand;
    }
    else if (m_operator == "*")
    {
        m_value *= operand;
    }
    else if (m_operator == "/")
    {
        m_value /= operand;
    }

    ui->lineEdit->setText(QString::number(m_value));
    m_waiting_for_second_operand = true;
    m_operator = op;
}

// 等于按钮槽函数
void MainWindow::equal_pressed()
{
    double operand = ui->lineEdit->text().toDouble();

    if (m_operator == "+")
    {
        m_value += operand;
    }
    else if (m_operator == "-")
    {
        m_value -= operand;
    }
    else if (m_operator == "*")
    {
        m_value *= operand;
    }
    else if (m_operator == "/")
    {
        m_value /= operand;
    }

    ui->lineEdit->setText(QString::number(m_value));
    m_operator = "";
    m_waiting_for_second_operand = true;
}

// 清除按钮槽函数
void MainWindow::clear_pressed()
{
    ui->lineEdit->setText("");
    m_value = 0.0;
    m_operator = "";
    m_waiting_for_second_operand = false;
}

这只是一个简单的实现，如果你想进一步改进你的计算器，你可以添加更多功能，例如括号、求平方根等。