qt5实现计算器

旧城等待， 2022-03-09 11:55 265阅读 0赞

（1）取出按钮中的字符

QString line = ui->pushButton1->text() //取出按钮pushButton1中的字符存放到line中

（2）设置输入框中显示的内容

ui->lineEdit->setText(line); //设置输入框lineEdit中显示的内容，line为要显示的内容

（3）将整形、浮点型、数值转换成字符

ui->lineEdit->setText(QString::number(sum)); //将浮点型转换成字符

（4）addwidgt说明：

//放置一个控件到一个单元格  
    void    addWidget ( QWidget * widget, int row, int column, Qt::Alignment alignment = 0 )  
     //如果放置的控件超出一个单元格，则使用该方法  
    void    addWidget ( QWidget * widget, int fromRow, int fromColumn, int rowSpan, int columnSpan, Qt::Alignment alignment = 0 )  
    参数说明：
        1）row：指放置控件的网格行号（行号从0开始）；
        2）colum：指放置控件的网格列号（从0开始）；
        3）alignment：对齐方式。
        4）fromRow：指放置控件的起始网格行号；
        5）fromColumn：指放置控件的起始网格列号；
        6）rowSpan：指放置控件占多少行；
        7）columnSpan：指放置控件占多少列。

计算器功能：对整数实现+、-、\*、/编辑框的小功能

1,实现代码如下  
main.cpp

#include "mainwindow.h"
    #include <QApplication>
    
    int main(int argc, char *argv[])
    {
    
        QApplication a(argc, argv);
    
        MainWindow w;
    
        w.show();
    
        w.setFixedSize(400,300);
    
        w.setWindowTitle("计算器");
    
        w.myLayout();
    
        return a.exec();
    
    }

mainwindow.h

#ifndef MAINWINDOW_H
    #define MAINWINDOW_H
    
    #include <QMainWindow>
    #include <QPushButton>
    #include <QLineEdit>
    
    class MainWindow : public QMainWindow
    {
        Q_OBJECT
    
    protected:
    
        int num1,num2,result; //标记第一个数，第二个数和结果
    
        int operat; //运算符号
    
        int operat_flag;//标记是否输入符号
    
        QLineEdit *data;
    
        QPushButton *button_0;
    
        QPushButton *button_1;
    
        QPushButton *button_2;
    
        QPushButton *button_3;
    
        QPushButton *button_4;
    
        QPushButton *button_5;
    
        QPushButton *button_6;
    
        QPushButton *button_7;
    
        QPushButton *button_8;
    
        QPushButton *button_9;
    
        QPushButton *button_ce;
    
        QPushButton *button_jia;
    
        QPushButton *button_jian;
    
        QPushButton *button_cheng;
    
        QPushButton *button_chu;
    
        QPushButton *button_result;
    
        QString s;
     
    public:
    
        MainWindow(QWidget *parent = 0);
    
        ~MainWindow();
    
    public:
    
        void myLayout();
    
        void operation();
    
        void readNum(int num);
    
        void init_data();
    
    private slots:
    
        void button_0_clicked();
    
        void button_1_clicked();
    
        void button_2_clicked();
    
        void button_3_clicked();
    
        void button_4_clicked();
    
        void button_5_clicked();
    
        void button_6_clicked();
    
        void button_7_clicked();
    
        void button_8_clicked();
    
        void button_9_clicked();
    
        void button_ce_clicked();
    
        void button_result_clicked();
    
        void button_cheng_clicked();
    
        void button_chu_clicked();
    
        void button_jia_clicked();
    
        void button_jian_clicked();
    
    };
    #endif

mainwindow.cpp

#include "mainwindow.h"
    
    #include <QPushButton>
    
    #include <QLineEdit>
    
    #include <QGridLayout>
    
    MainWindow::MainWindow(QWidget *parent)
    
        : QMainWindow(parent)
    {
    
    }
    
    
    void MainWindow::myLayout(){
    
        QWidget *centerWindow = new QWidget;
    
        this->setCentralWidget(centerWindow);
    
        s = "";
    
        init_data();
    
        data = new QLineEdit("");
    
        button_0 = new QPushButton("0");
    
        button_1 = new QPushButton("1");
    
        button_2 = new QPushButton("2");
    
        button_3 = new QPushButton("3");
    
        button_4 = new QPushButton("4");
    
        button_5 = new QPushButton("5");
    
        button_6 = new QPushButton("6");
    
        button_7 = new QPushButton("7");
    
        button_8 = new QPushButton("8");
    
        button_9 = new QPushButton("9");
    
        button_ce = new QPushButton("CE");
    
        button_jia = new QPushButton("+");
    
        button_jian = new QPushButton("-");
    
        button_cheng = new QPushButton("*");
    
        button_chu = new QPushButton("/");
    
        button_result = new QPushButton("=");
    
        data->setFixedHeight(30);
    
        button_0->setMinimumHeight(50);
    
        button_1->setMinimumHeight(50);
    
        button_2->setMinimumHeight(50);
    
        button_3->setMinimumHeight(50);
    
        button_4->setMinimumHeight(50);
    
        button_5->setMinimumHeight(50);
    
        button_6->setMinimumHeight(50);
    
        button_7->setMinimumHeight(50);
    
        button_8->setMinimumHeight(50);
    
        button_9->setMinimumHeight(50);
    
        button_ce->setMinimumHeight(50);
    
        button_jia->setMinimumHeight(50);
    
        button_jian->setMinimumHeight(50);
    
        button_cheng->setMinimumHeight(50);
    
        button_chu->setMinimumHeight(50);
    
        button_result->setMinimumHeight(50);
    
        //连接信号
    
        connect(button_0,SIGNAL(clicked(bool)),this,SLOT(button_0_clicked()));
    
        connect(button_1,SIGNAL(clicked(bool)),this,SLOT(button_1_clicked()));
    
        connect(button_2,SIGNAL(clicked(bool)),this,SLOT(button_2_clicked()));
    
        connect(button_3,SIGNAL(clicked(bool)),this,SLOT(button_3_clicked()));
    
        connect(button_4,SIGNAL(clicked(bool)),this,SLOT(button_4_clicked()));
    
        connect(button_5,SIGNAL(clicked(bool)),this,SLOT(button_5_clicked()));
    
        connect(button_6,SIGNAL(clicked(bool)),this,SLOT(button_6_clicked()));
    
        connect(button_7,SIGNAL(clicked(bool)),this,SLOT(button_7_clicked()));
    
        connect(button_8,SIGNAL(clicked(bool)),this,SLOT(button_8_clicked()));
    
        connect(button_9,SIGNAL(clicked(bool)),this,SLOT(button_9_clicked()));
    
        connect(button_jia,SIGNAL(clicked(bool)),this,SLOT(button_jia_clicked()));
    
        connect(button_jian,SIGNAL(clicked(bool)),this,SLOT(button_jian_clicked()));
    
        connect(button_cheng,SIGNAL(clicked(bool)),this,SLOT(button_cheng_clicked()));
    
        connect(button_chu,SIGNAL(clicked(bool)),this,SLOT(button_chu_clicked()));
    
        connect(button_ce,SIGNAL(clicked(bool)),this,SLOT(button_ce_clicked()));
    
        connect(button_result,SIGNAL(clicked(bool)),this,SLOT(button_result_clicked()));
    
        QGridLayout * layout = new QGridLayout;
     
        layout->addWidget(data,1,1,1,4,Qt::Alignment()); //控件超出一个单元格,数据输出口
    
        layout->addWidget(button_1,2,1,Qt::Alignment());
    
        layout->addWidget(button_2,2,2,Qt::Alignment());
    
        layout->addWidget(button_3,2,3,Qt::Alignment());
    
        layout->addWidget(button_jia,2,4,Qt::Alignment());
    
        layout->addWidget(button_4,3,1,Qt::Alignment());
    
        layout->addWidget(button_5,3,2,Qt::Alignment());
    
        layout->addWidget(button_6,3,3,Qt::Alignment());
    
        layout->addWidget(button_jian,3,4,Qt::Alignment());
    
        layout->addWidget(button_7,4,1,Qt::Alignment());
    
        layout->addWidget(button_8,4,2,Qt::Alignment());
    
        layout->addWidget(button_9,4,3,Qt::Alignment());
    
        layout->addWidget(button_cheng,4,4,Qt::Alignment());
    
        layout->addWidget(button_ce,5,1,Qt::Alignment());
    
        layout->addWidget(button_0,5,2,Qt::Alignment());
    
        layout->addWidget(button_result,5,3,Qt::Alignment());
    
        layout->addWidget(button_chu,5,4,Qt::Alignment());
    
        layout->setMargin(12);
    
        centerWindow->setLayout(layout);
    
    }
     
    MainWindow::~MainWindow()
    {
     
    
    }
    
    void MainWindow::init_data()
    {
    
        num1 = 0;
    
        num2 = 0;
    
        operat_flag = 0;
    
    }
    
     
    
    void MainWindow::readNum(int num)
    
    {
    
          //如果是第一个操作数
    
          if(operat_flag == 0){
    
              num1 = num1 * 10 + num;
    
          }
    
          //如果是第二个操作数
    
          else{
    
              num2 = num2 * 10 + num;
    
          }
    
    }
    
     
    
    void MainWindow::operation()
    
    {
    
        switch(operat){
    
        case 1:
    
            result = num1 + num2;
    
            break;
    
        case 2:
    
            result = num1 - num2;
    
            break;
    
        case 3:
    
            result = num1 * num2;
    
            break;
    
        case 4:
    
            result = num1 / num2;
    
            break;
    
        }
    
        //把结果存到num1中，清零num2
    
        num1 = result;
    
        num2 = 0;
    
        s = QString::number(result,10);
    
    }
    
     
    void MainWindow::button_0_clicked(){
    
        s += "0";
    
        data->setText(s);
    
        readNum(0);
    
    }
    
    
    void MainWindow::button_1_clicked(){
    
        s += "1";
    
        data->setText(s);
    
        readNum(1);
    
    }
    
    
    void MainWindow::button_2_clicked(){
    
        s += "2";
    
        data->setText(s);
    
        readNum(2);
    
    }
     
    void MainWindow::button_3_clicked(){
    
        s += "3";
    
        data->setText(s);
    
        readNum(3);
    
    }
    
    void MainWindow::button_4_clicked(){
    
        s += "4";
    
        data->setText(s);
    
        readNum(4);
    
    }
     
    void MainWindow::button_5_clicked(){
    
        s += "5";
    
        data->setText(s);
    
        readNum(5);
    
    }
    
    void MainWindow::button_6_clicked(){
    
        s += "6";
    
        data->setText(s);
    
        readNum(6);
    
    }
     
    void MainWindow::button_7_clicked(){
    
        s += "7";
    
        data->setText(s);
    
        readNum(7);
    
    }
    
     
    void MainWindow::button_8_clicked(){
    
        s += "8";
    
        data->setText(s);
    
        readNum(8);
    
    }
     
    
    void MainWindow::button_9_clicked(){
    
        s += "9";
    
        data->setText(s);
    
        readNum(9);
    
    }
    
    
    void MainWindow::button_ce_clicked(){
    
        s = "";
    
        data->setText("");
    
        //初始化数据
    
        init_data();
    
    }
    
    void MainWindow::button_jia_clicked(){
    
        s += "+";
    
        data->setText(s);
    
        operat_flag = 1;
    
        operat = 1;
    
    }
    
    void MainWindow::button_jian_clicked(){
    
        s += "-";
    
        data->setText(s);
    
        operat_flag = 1;
    
        operat = 2;
    
    }
     
    void MainWindow::button_cheng_clicked(){
    
        s += "*";
    
        data->setText(s);
    
        operat_flag = 1;
    
        operat = 3;
    
    }
     
    void MainWindow::button_chu_clicked(){
    
        s += "/";
    
        data->setText(s);
    
        operat_flag = 1;
    
        operat = 4;
    
    }
    
    void MainWindow::button_result_clicked(){
    
        operation();
    
        QString a = QString::number(result,10);
    
        data->setText(a);
    
    }

完整代码连接：[https://download.csdn.net/download/qq\_40008325/11015502][https_download.csdn.net_download_qq_40008325_11015502]

[https_download.csdn.net_download_qq_40008325_11015502]: https://download.csdn.net/download/qq_40008325/11015502