Qt小项目（一）：四则运算计算器

#include "widget.h"
#include "ui_widget.h"
#include "string"
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    connect(ui->zero,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->one,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->two,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->three,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->four,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->five,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->six,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->seven,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->eight,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->nine,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    
    connect(ui->add,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->subs,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->multiply,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    connect(ui->divide,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    
    connect(ui->equals,SIGNAL(clicked()),this,SLOT(on_all_clicked()));
    
    connect(ui->clear,SIGNAL(clicked()),this,SLOT(on_all_clicked()));

}

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

void Widget::on_all_clicked()
{
    QString str = ui->oper1->text();
    QString str2 = ui->oper2->text();
    QPushButton *btn=qobject_cast<QPushButton*>(sender());
    static bool op1Check= false;
    static int oper;

    if(op1Check==false){//第一个数没有输入完成
        if(btn->objectName()=="zero"){
             str=str.append("0");
        }else if(btn->objectName()=="one"){
            str=str.append("1");
        }else if(btn->objectName()=="two"){
            str=str.append("2");
        }else if(btn->objectName()=="three"){
            str=str.append("3");
        }else if(btn->objectName()=="four"){
            str=str.append("4");
        }else if(btn->objectName()=="five"){
            str=str.append("5");
        }else if(btn->objectName()=="six"){
            str=str.append("6");
        }else if(btn->objectName()=="seven"){
            str=str.append("7");
        }else if(btn->objectName()=="eight"){
            str=str.append("8");
        }else if(btn->objectName()=="nine"){
            str=str.append("9");
        }

         ui->oper1->setText(str);//追加到显示框

         if(btn->objectName()=="add"){//输入 *** 作符，意味着第一个数输入完成
              ui->operation->setText("+");
              op1Check=true;
              oper=0;
         }else if(btn->objectName()=="subs"){
             ui->operation->setText("-");
               op1Check=true;
               oper=1;
         }else if(btn->objectName()=="multiply"){
             ui->operation->setText("*");
               op1Check=true;
               oper=2;
          }else if(btn->objectName()=="divide"){
             ui->operation->setText("/");
               op1Check=true;
               oper=3;
        }
}

     if(op1Check==true){//如果第一个数输入完成才输入第二个数

         if(btn->objectName()=="zero"){
              str2=str2.append("0");
         }else if(btn->objectName()=="one"){
             str2=str2.append("1");
         }else if(btn->objectName()=="two"){
             str2=str2.append("2");
         }else if(btn->objectName()=="three"){
             str2=str2.append("3");
         }else if(btn->objectName()=="four"){
             str2=str2.append("4");
         }else if(btn->objectName()=="five"){
             str2=str2.append("5");
         }else if(btn->objectName()=="six"){
             str2=str2.append("6");
         }else if(btn->objectName()=="seven"){
             str2=str2.append("7");
         }else if(btn->objectName()=="eight"){
             str2=str2.append("8");
         }else if(btn->objectName()=="nine"){
             str2=str2.append("9");
         }
          ui->oper2->setText(str2);

     }



     if(btn->objectName()=="equals"){//输入等于号之后的 *** 作
         QString strRes;
        int num1 = str.toInt() ;
        int num2 = str2.toInt();
        int res;
        QString op = ui->operation->text();
        if(oper==0){
             res = num1+num2;
        }else if(oper==1){
             res = num1-num2;
        }else if(oper==2){
             res = num1*num2;
        }else if(oper==3){
             res = num1/num2;
        }

        strRes=strRes.setNum(res);
        strRes=strRes.prepend("=");
        strRes=strRes.prepend(str2);//追加 *** 作数和 *** 作符成为表达式显示

        if(oper==0){
             strRes=strRes.prepend("+");
        }else if(oper==1){
              strRes=strRes.prepend("-");
        }else if(oper==2){
             strRes=strRes.prepend("*");
        }else if(oper==3){
             strRes=strRes.prepend("/");
        }

        strRes=strRes.prepend(str);


        ui->result->setText(strRes);
        op1Check=false;
        ui->oper1->setText("");
        ui->oper2->setText("");
        ui->operation->setText("");

     }

     if(btn->objectName()=="clear"){//清除 *** 作
         op1Check=false;
         ui->oper1->setText("");
         ui->oper2->setText("");
         ui->operation->setText("");
         ui->result->setText("");
     }





}