Qt实现简易计算机

 这里我是用的qt图形界面直接创建按键转接槽函数，大家可以也可以使用代码创建界面，有时间的可以试试。

这是.h文件

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

private slots:
    void on_close_clicked();

    void on_Button_add_clicked();

    void on_Button_sub_clicked();

    void on_Button_mul_clicked();

    void on_Button_dev_clicked();

    void on_Button_prrcent_clicked();

    void on_Button_1_clicked();

    void on_Button_2_clicked();

    void on_Button_3_clicked();

    void on_Button_4_clicked();

    void on_Button_5_clicked();

    void on_Button_6_clicked();

    void on_Button_7_clicked();

    void on_Button_8_clicked();

    void on_Button_9_clicked();

    void on_Button_0_clicked();

    void on_Button_d_clicked();

    void on_Button_equal_clicked();

    void on_Button_clear_clicked();

    void on_Button_delete_clicked();

private:
    Ui::Widget *ui;
    QString op1;
    QString op2;
    int flag;
};

#endif // WIDGET_H

.cpp文件

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    op1 = "";
    op2 = "";
    flag = 0;//设置标志位简化后面的操作
}

Widget::~Widget()
{
    delete ui;
}
void Widget::on_close_clicked()//退出计算机
{
    this->close();
}

void Widget::on_Button_add_clicked()
{
    flag = 1;
}

void Widget::on_Button_sub_clicked()
{
    flag = 2;
}

void Widget::on_Button_mul_clicked()
{
    flag = 3;
}

void Widget::on_Button_dev_clicked()
{
    flag = 4;
}


void Widget::on_Button_prrcent_clicked()
{
    flag = 5;
}



void Widget::on_Button_1_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "1";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "1";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_2_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "2";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "2";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_3_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "3";
        ui->textEdit->setText(op1);
    }
    else
    {
        op1 = "";
        op2 = op2 + "3";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_4_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "4";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "4";
        ui->textEdit->setText(op2);
    }
}


void Widget::on_Button_5_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "5";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "5";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_6_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "6";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "6";
        ui->textEdit->setText(op2);
    }
}


void Widget::on_Button_7_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "7";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "7";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_8_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "8";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "8";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_9_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "9";
        ui->textEdit->setText(op1);
    }
    else
    {
        op2 = op2 + "9";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_0_clicked()
{
    if(flag == 0)
    {
        op1 = "";
        op1 = op1 + "0";
        ui->textEdit->setText(op1);
    }
    else
    {
        op1 = "";
        op2 = op2 + "0";
        ui->textEdit->setText(op2);
    }
}


void Widget::on_Button_d_clicked()//小数点，此处逻辑上没有完全完善，大家可以自行完善
{

    if(flag == 0)
    {
        if(op1 == "")
            return ;
        op1 = op1 + ".";
        ui->textEdit->setText(op1);
    }
    else
    {
        if(op2 == "")
            return ;
        op2 = op2 + ".";
        ui->textEdit->setText(op2);
    }
}

void Widget::on_Button_equal_clicked()// =
{
    float result;
    float number1;
    float number2;
    number1 = op1.toFloat();
    number2 = op2.toFloat();
    if(flag == 1)
    {
        result = number1 + number2;
    }
    if(flag == 2)
    {
        result = number1 - number2;
    }
    if(flag == 3)
    {
        result = number1 * number2;
    }
    if(flag == 4)
    {
        result = number1 / number2;
    }
    if(flag == 5)
    {
        result = number1 / number2; // % 百分之多少还没实现，大家可以根据直接逻辑去实现，我就偷懒了
    }
    QString str;
    str = str.number(result);
    ui->textEdit->setText(str);
    flag = 0;
    op1 = QString::number(result);  //数字转换成字符串后继续运行
    op2 = "";
}


void Widget::on_Button_clear_clicked()//清空
{
    ui->textEdit->setText("");
    flag = 0;
    op1 = "";
    op2 = "";
}

void Widget::on_Button_delete_clicked()//删除一位
{
    if(flag == 0)
    {
        op1.chop(1);//剪切掉最后一位
        ui->textEdit->setText(op1);
    }
    else
    {
        op2.chop(1);
        ui->textEdit->setText(op2);
    }

}

有些许逻辑上没有实现，大家可根据自己需要完善