calculator计算器实现

.pro文件

#-------------------------------------------------
#
# Project created by QtCreator 2024-01-04T11:02:23
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = calculator
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0


SOURCES += \
        main.cpp \
        widget.cpp

HEADERS += \
        widget.h

FORMS += \
        widget.ui

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include<QStack>
#include<string.h>
namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

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

private slots:
    void on_oneButton_clicked();

    void on_twoButton_clicked();

    void on_threeButton_clicked();

    void on_foutButton_clicked();

    void on_fiveButton_clicked();

    void on_sixButton_clicked();

    void on_sevenButton_clicked();

    void on_eightButton_clicked();

    void on_nineButton_clicked();

    void on_zeroButton_clicked();

    void on_addButton_clicked();

    void on_subButton_clicked();

    void on_mulButton_clicked();

    void on_divButton_clicked();

    void on_leftButton_clicked();

    void on_rightButton_clicked();

    void on_clearButton_clicked();

    void on_delButton_clicked();

    void on_equalButton_clicked();

private:
    Ui::Widget *ui;
    QString expression;
    int Priority(char ch);
};

#endif // WIDGET_H

main.cpp

#include "widget.h"
#include <QApplication>

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

    return a.exec();
}

widge.cpp

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

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setMaximumSize(200,320);//此处可以设置最大宽度和高度
    this->setMinimumSize(200,320);
    this->setWindowTitle("计算器");

        //给一个控件换字体
    QFont f("仿宋",15);
    ui->mainLineEdit->setFont(f);

        //给控件换图片
    QIcon con("D:\\QTProject\\QtOnline\\calculator\\回退.png");           //不使用资源来创建图标，打包时可能会导致图片无法显示找到。
    ui->delButton->setIcon(con);
        //改变按钮背景色


    ui->equalButton->setStyleSheet("background :yellow");

}

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

void Widget::on_oneButton_clicked()
{
    expression +="1";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_twoButton_clicked()
{
    expression +="2";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_threeButton_clicked()
{
    expression+="3";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_foutButton_clicked()
{
   expression +="4";
   ui->mainLineEdit->setText(expression);
}


void Widget::on_fiveButton_clicked()
{
    expression +="5";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_sixButton_clicked()
{
    expression +="6";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_sevenButton_clicked()
{
    expression +="7";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_eightButton_clicked()
{
    expression +="8";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_nineButton_clicked()
{
    expression +="9";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_zeroButton_clicked()
{
    expression +="0";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_addButton_clicked()
{
    expression +="+";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_subButton_clicked()
{
    expression +="-";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_mulButton_clicked()
{
    expression +="*";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_divButton_clicked()
{
    expression +="/";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_leftButton_clicked()
{
    expression +="(";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_rightButton_clicked()
{
    expression +=")";
    ui->mainLineEdit->setText(expression);
}

void Widget::on_clearButton_clicked()
{
    expression.clear();
    ui->mainLineEdit->clear();
}

void Widget::on_delButton_clicked()
{
    expression.chop(1);     //删除最后一个字符串，chop函数。
    ui->mainLineEdit->setText(expression);

}

void Widget::on_equalButton_clicked()
{
    QStack<int> s_num, s_opt;

    char opt[128] = {0};
    int i = 0, tmp = 0, num1, num2;

    //把QString转换成char *
    QByteArray ba;
    ba.append(expression);   //把QString转换成QByteArray
    strcpy(opt, ba.data());  //data可以把QByteArray转换成const char *

    while (opt[i] != '\0' || s_opt.empty() != true)
    {
        if (opt[i] >= '0' && opt[i] <= '9')
        {
            tmp = tmp * 10 + opt[i] - '0';
            i++;
            if (opt[i] < '0' || opt[i] > '9')
            {
                s_num.push(tmp);
                tmp = 0;
            }
        }
        else           //操作符
        {
            if (s_opt.empty() == true || Priority(opt[i]) > Priority(s_opt.top()) ||
                    (s_opt.top() == '(' && opt[i] != ')'))
            {
                s_opt.push(opt[i]);
                i++;
                continue;
            }

            if (s_opt.top() == '(' && opt[i] == ')')
            {
                s_opt.pop();
                i++;
                continue;
            }

            if (Priority(opt[i]) <= Priority(s_opt.top()) || (opt[i] == ')' && s_opt.top() != '(') ||
                (opt[i] == '\0' && s_opt.empty() != true))
            {
                char ch = s_opt.top();
                s_opt.pop();
                switch(ch)
                {
                    case '+':
                        num1 = s_num.top();
                        s_num.pop();
                        num2 = s_num.top();
                        s_num.pop();
                        s_num.push(num1 + num2);
                        break;
                    case '-':
                        num1 = s_num.top();
                        s_num.pop();
                        num2 = s_num.top();
                        s_num.pop();
                        s_num.push(num1 - num2);
                        break;
                    case '*':
                        num1 = s_num.top();
                        s_num.pop();
                        num2 = s_num.top();
                        s_num.pop();
                        s_num.push(num1 * num2);
                        break;
                    case '/':
                        num1 = s_num.top();
                        s_num.pop();
                        num2 = s_num.top();
                        s_num.pop();
                        s_num.push(num2 / num1);
                        break;
                }
            }
        }
    }
    ui->mainLineEdit->setText(QString::number(s_num.top()));
    expression.clear();
}

int Widget::Priority(char ch)
{
    switch(ch)
    {
        case '(':
            return 3;
        case '*':
        case '/':
            return 2;
        case '+':
        case '-':
            return 1;
        default:
            return 0;
    }
}