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));
}