Qt学习笔记（二）---实现四则运算

用Qt实现一个可以实现四则运算的计算器：

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

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

    QObject::connect(ui->calButton,SIGNAL(clicked()),this,SLOT(calSlot()));
}

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

//goto click ---->on_calButton_clicked()
void MainWindow::calSlot()
{
    int first=ui->firstLineEdit->text().toInt();
    int second=ui->secondLineEdit->text().toInt();
    int result;
    if(ui->comboBox->currentIndex()==0)
     {
        result=first+second;
        //调用静态方法
        QMessageBox::information(this,"Result",QString::number(result));
     }
    if(ui->comboBox->currentIndex()==1)
     {
        result=first-second;
        //调用静态方法
        QMessageBox::information(this,"Result",QString::number(result));
     }
    if(ui->comboBox->currentIndex()==2)
     {
        result=first*second;
        //调用静态方法
        QMessageBox::information(this,"Result",QString::number(result));
     }
    if(ui->comboBox->currentIndex()==3)
      {
        if(second==0)
          {
            QMessageBox::warning(this,"Error Message","Second Can't be Zeros!!");
            return;

           }
        result=first/second;
        //调用静态方法
        QMessageBox::information(this,"Result",QString::number(result));

      }
    //setText 设置文本
    ui->resultLineEdit->setText(QString::number(result));
}