使用QT做一個簡易計算器

由於比較簡單下面就直接給出原始碼，直接拷貝就可以使用

標頭檔案

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include
#include

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void on_clicked();
void on_bt_eq_clicked();
void on_bt_del_clicked();

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

程式碼塊

#include “mainwindow.h”
#include “ui_mainwindow.h”

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

/*實現按鈕C的功能：按鈕按下，編輯框清空*/
connect(ui->bt_zero,SIGNAL(clicked(bool)),ui->lineEdit,SLOT(clear()));

connect(ui->bt_0,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_1,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_2,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_3,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_4,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_5,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_6,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_7,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_8,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
connect(ui->bt_9,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
/*加*/
connect(ui->bt_add,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
/*乘*/
connect(ui->bt_mul,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
/*減*/
connect(ui->bt_sub,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
/*除*/
connect(ui->bt_div,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));
/*點*/
connect(ui->bt_dot,SIGNAL(clicked(bool)),this,SLOT(on_clicked()));

/*退格*/
//connect(ui->bt_del,SIGNAL(clicked(bool)),this,SLOT(on_bt_del_clicked()));

/*等於號*/
connect(ui->bt_eq,SIGNAL(clicked(bool)),this,SLOT(on_bt_eq_clicked()));

/*歸0*/
connect(ui->bt_zero,SIGNAL(clicked(bool)),ui->lineEdit,SLOT(clear()));

}
/析構/
MainWindow::~MainWindow()
{

delete ui;

}

/數字輸入設定/
void MainWindow::on_clicked()
{
/採用標準轉換函式/
QPushButton * bt = dynamic_cast <QPushButton *> (this->sender());
qDebug() << bt->text();

/*提取編輯框內容追加，追加後再顯示*/
QString str = ui->lineEdit->text();
str.append(bt->text());
ui->lineEdit->setText(str);

}

/退格符號處理/
void MainWindow::on_bt_del_clicked()
{
/獲取編輯框的內容/
QString str = ui->lineEdit->text();

/*left函式，中間引數是取字串的長度*/
str = str.left( str.size() -1 );

/*qDebug()除錯找到退格造成退格兩次的原因：用了轉到槽，又用了connect*/
qDebug()<<str;

ui->lineEdit->setText(str);

}

/等於符號的處理/
void MainWindow::on_bt_eq_clicked()
{
/獲取編輯框的內容/
QString str = ui->lineEdit->text();

/*先用temp儲存一下需要做運算的算式*/
QString temp = str;
if(str.contains("+"))
{
    /*以加號分割*/
    QStringList data = str.split("+");

    /*運算元1*/
    QString str1 = data.at(0);
    qDebug()<<data.at(0);

    /*運算元2*/
    QString str2 = data.at(1);
    qDebug()<<data.at(1);

    /*輸出是字串，計算是數字，這裡就多轉換*/
    double sum1 = str1.toDouble();
    double sum2 = str2.toDouble();
    double num = sum1 + sum2;
    str = QString::number(num);
    /*列印計算結果*/
    ui->lineEdit->setText(str);

    /*把操作和結果追加到歷史記錄裡面*/
    temp.append("=");
    temp.append(str);
    ui->textEdit_history->append(temp);
}
else if(str.contains("-"))
{
    /*以減號分割*/
    QStringList data = str.split("-");

    /*運算元1*/
    QString str1 = data.at(0);
    qDebug()<<data.at(0);

    /*運算元2*/
    QString str2 = data.at(1);
    qDebug()<<data.at(1);

    /*輸出是字串，計算是數字，這裡就多轉換*/
    double sum1 = str1.toDouble();
    double sum2 = str2.toDouble();
    double num = sum1 - sum2;
    str = QString::number(num);

    /*列印計算結果*/
    ui->lineEdit->setText(str);

    /*把操作和結果追加到歷史記錄裡面*/
    temp.append("=");
    temp.append(str);
    ui->textEdit_history->append(temp);
}
else if(str.contains("*"))
{
    /*以乘號分割*/
    QStringList data = str.split("*");

    /*運算元1*/
    QString str1 = data.at(0);
    qDebug()<<data.at(0);

    /*運算元2*/
    QString str2 = data.at(1);
    qDebug()<<data.at(1);

    /*輸出是字串，計算是數字，這裡就多轉換*/
    double sum1 = str1.toDouble();
    double sum2 = str2.toDouble();
    double num = sum1 * sum2;
    str = QString::number(num);

    /*列印計算結果*/
    ui->lineEdit->setText(str);

    /*把操作和結果追加到歷史記錄裡面*/
    temp.append("=");
    temp.append(str);
    ui->textEdit_history->append(temp);
}
else if(str.contains("/"))
{
    /*以除號分割*/
    QStringList data = str.split("/");

    /*運算元1*/
    QString str1 = data.at(0);
    qDebug()<<data.at(0);

    /*運算元2*/
    QString str2 = data.at(1);
    qDebug()<<data.at(1);

    /*輸出是字串，計算是數字，這裡就多轉換*/
    double sum1 = str1.toDouble();
    double sum2 = str2.toDouble();

    /*這裡沒有判斷除數是0，因為執行之後除以0會顯示def*/
    double num = sum1 / sum2;

    str = QString::number(num);

    /*列印計算結果*/
    ui->lineEdit->setText(str);

    /*把操作和結果追加到歷史記錄裡面*/
    temp.append("=");
    temp.append(str);
    ui->textEdit_history->append(temp);
}

}

main檔案

#include “mainwindow.h”
#include

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();

return a.exec();

}

介面

介面是直接用Ui畫的，由於是初次接觸，沒有使用純程式碼敲。

ui介面圖

控制元件名字

如果有不懂的可以直接私信我