C++结合QT实现带有优先级的计算器功能

时间：2022-11-23 14:43:36

代码

MyCalculator.h

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#pragma once
 
#include <QtWidgets/QMainWindow>
#include <QStack>
#include <QString>
#include "ui_MyCalculator.h"
 
class MyCalculator : public QMainWindow
{
  Q_OBJECT
 
public:
  MyCalculator(QWidget *parent = Q_NULLPTR);
    
/*  void setnum1(int num);
    void setnum2(int num);
    void setflag(int f);
    int calculartor();
*/
 
 
private slots:
    void on_number_Button_clicked();
    void on_action_Button_clicked();
    void on_comma_Button_clicked();
    void on_action_Button_c_clicked();
    void on_action_Button_d_clicked();
    void on_action_Button_e_clicked();
 
/*
    void on_action_Button_equal_clicked();
    void on_number_Button_clicked();
    void on_action_Button_clicked();
    void on_action_Button_c_clicked();
*/
 
private:
  Ui::MyCalculatorClass ui;
 
};

MyCalculator.main

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#include "MyCalculator.h"
#include <QtWidgets/QApplication>
 
int main(int argc, char *argv[])
{
  QApplication a(argc, argv);
  MyCalculator w;
  w.show();
  return a.exec();
}

MyCalculator.cpp

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#include "MyCalculator.h"
 
#include<iostream>
using namespace std;
#include<stack>
#include<vector>
#include<cstdlib>
#include<limits.h>
 
MyCalculator::MyCalculator(QWidget *parent)
  : QMainWindow(parent)
{
  ui.setupUi(this);
    setWindowTitle(QStringLiteral("计算器"));
    ui.textBrowser->setFontPointSize(28);
 
    connect(ui.pushButton0, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton1, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton2, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton3, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton4, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton5, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton6, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton7, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton8, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton9, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
 
    connect(ui.pushButton_add, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_div, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_mul, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_sub, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_right, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_left, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_dian, SIGNAL(clicked()), this, SLOT(on_comma_Button_clicked()));
 
 
    connect(ui.pushButton_del, SIGNAL(clicked()), this, SLOT(on_action_Button_d_clicked()));
    connect(ui.pushButton_re, SIGNAL(clicked()), this, SLOT(on_action_Button_c_clicked()));
    connect(ui.pushButton_equ, SIGNAL(clicked()), this, SLOT(on_action_Button_e_clicked()));
    /*
    //没有优先级的计算器
    connect(ui.pushButton0, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton1, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton2, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton3, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton4, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton5, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton6, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton7, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton8, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
    connect(ui.pushButton9, SIGNAL(clicked()), this, SLOT(on_number_Button_clicked()));
 
    connect(ui.pushButton_add, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_div, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_mul, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
    connect(ui.pushButton_sub, SIGNAL(clicked()), this, SLOT(on_action_Button_clicked()));
 
    connect(ui.pushButton_re, SIGNAL(clicked()), this, SLOT(on_action_Button_c_clicked()));
 
    connect(ui.pushButton_equ, SIGNAL(clicked()), this, SLOT(on_action_Button_equal_clicked()));
    */
 
}
void MyCalculator::on_number_Button_clicked()
{
    QPushButton *btn = qobject_cast<QPushButton*>(sender());
    QString number = btn->text();
    QString ss = ui.textBrowser->toPlainText();
    ui.textBrowser->clear();
    ui.textBrowser->append(ss + number);
}
void MyCalculator::on_action_Button_clicked()//操作符
{
    QPushButton *btn = qobject_cast<QPushButton*>(sender());
    QString action = btn->text();
    QString ss = ui.textBrowser->toPlainText();
    ui.textBrowser->clear();
    ui.textBrowser->append(ss + action);
}
void MyCalculator::on_comma_Button_clicked()//小数点
{
    QPushButton *btn = qobject_cast<QPushButton*>(sender());
    QString action = btn->text();
    QString ss = ui.textBrowser->toPlainText();
    ui.textBrowser->clear();
    ui.textBrowser->append(ss + action);
}
void MyCalculator::on_action_Button_c_clicked()//重置输入框里的内容
{
    ui.textBrowser->clear();
}
void MyCalculator::on_action_Button_d_clicked()//删除表达式中最后一个符号
{
    QString ss = ui.textBrowser->toPlainText();//在一行
    ss = ss.left(ss.length() - 1);
    ui.textBrowser->clear();
    ui.textBrowser->setText(ss);
}
bool isNum(QString ch)
{
    if (ch >= '0' && ch <= '9' || ch == '.')
        return true;
    else
        return false;
}
bool isOperate(QString ch)
{
    if (ch == '+' || ch == '-' || ch == '*' || ch == '/' || ch == '(' || ch == ')' )
        return true;
    else
        return false;
}
int level(QString ch) {//优先级设置
    if(ch == '(')
        return 5;
    else if (ch == '*' || ch== '/')
        return 4;
    else if (ch == '+' || ch == '-')
        return 3;
    else if (ch == ')')
        return 2;
}
double calcu(double a ,double b, QString c)
{
    double result = 0;
    if (c == '+')
        result = b + a;
    else if (c == '-')
        result = b - a;
    else if (c == '*')
        result = b * a;
    else if (c == '/')
        result = b / a;
    else
        result = INT_MAX;
    return result;
}
double getjieguo(QString input)
{
    QStack<double> Num;
    QStack<QString> Act;
    int a = input.length();
    for(int i=0;i< a;i++)
    {
        int flag = 0;//用来判断是否是数字
        int xiaoshu = 1;//用来判断是否是小数部分
        double number = 0;//暂存数字
        QString frist = input.left(1);
        while (isNum(frist))                //连续的数字转化为一个整数
        {
            if (frist == '.' || xiaoshu == 2)
            {
                number = frist.toDouble() / 10 + number;
                xiaoshu = 2;
            }
            else
            {
                number = number * 10 + frist.toInt();
            }
            input = input.right(input.length() - 1);
            frist = input.left(1);
            flag = 1;
        }
        if (flag == 1)
            Num.push(number);
 
        if (isOperate(frist))
        {
            if (!Act.empty() && (level(Act.top()) > level(frist)))
            {
                    double a = Num.pop();
                    double b = Num.pop();
                    QString c = Act.pop();
                    double result = calcu(a, b, c);
                    Num.push(result);
                    if (frist != ')')
                        Act.push(frist);
                    input = input.right(input.length() - 1);
                    frist = input.left(1);
            }
            else if (!Act.empty() && (level(Act.top()) <= level(frist)))
            {
                if (frist != '(')
                    Act.push(frist);
                input = input.right(input.length() - 1);
                frist = input.left(1);
            }
            else if(Act.empty())                //操作符第一次入符号栈
            {
                Act.push(frist);
                input = input.right(input.length() - 1);
                frist = input.left(1);
            }
        }
        if (frist == '=')//支持得到结果后仍可以继续运算
        {
            Num.clear();
            Act.clear();
            input = input.right(input.length() - 1);
            frist = input.left(1);
        }
 
        if (i + 1 >= a)              //当表达式都进栈后，只要符号栈不为空就继续执行
        {
            while (!Act.empty())
            {
                double a1 = Num.pop();
                double b1 = Num.pop();
                QString c1 = Act.pop();
                double result = calcu(a1, b1, c1);
                Num.push(result);
            }
        }
    }
 
    return Num.top();
 
}
void MyCalculator::on_action_Button_e_clicked()
{
    QString input = ui.textBrowser->toPlainText();//将输入框里的内容给input
    double value = getjieguo(input);//将表达式传给getjieguo来将数字和操作符分别入对应的栈
    ui.textBrowser->clear();
    ui.textBrowser->append(input + "=" + QString::number(value));//将结果的类型由数字转化为QString
 
}
/*
void MyCalculator::setnum1(int num)
{
    num1 = num;
}
void MyCalculator::setnum2(int num)
{
    num2 = num;
}
void MyCalculator::setflag(int f)
{
    flag = f;
}
int MyCalculator::calculartor()
{
    int result = 0;
    if (flag == 1)
        result = num1 + num2;
    else if (flag == 2)
        result = num1 - num2;
    else if (flag == 3)
        result = num1 * num2;
    else if (flag == 4)
    {
        if (num2 == 0)
            setflag(5);
        else
            result = num1 / num2;
    }
    else
        result = 0;
 
    return result;
}
 
void MyCalculator::on_action_Button_c_clicked()
{
    ui.textBrowser->clear();
    setnum1(0);
    setnum2(0);
    setflag(0);
}
 
void MyCalculator::on_number_Button_clicked()
{
    QPushButton *btn = qobject_cast<QPushButton*>(sender());
    QString number = btn->text();
    QString ss = ui.textBrowser->toPlainText();
    ui.textBrowser->clear();
    ui.textBrowser->append(ss + number);
}
 
void MyCalculator::on_action_Button_clicked()
{
    int number = ui.textBrowser->toPlainText().toInt();
    setnum1(number);
    QPushButton *btn = qobject_cast<QPushButton*>(sender());
    QString action = btn->text();
    ui.textBrowser->clear();
    if (action == "+")
        setflag(1);
    else if (action == "-")
        setflag(2);
    else if (action == "*")
        setflag(3);
    else
        setflag(4);
 
}
 
void MyCalculator::on_action_Button_equal_clicked() {
    int number = ui.textBrowser->toPlainText().toInt();
    setnum2(number);
    int res = calculartor();
    ui.textBrowser->clear();
    if (flag == 5)
        ui.textBrowser->append(QStringLiteral("不能除于0，请重新输入"));
    else
        ui.textBrowser->append(QString::number(res));
}
*/

测试

 

表达式 结果
2*3+6-(1+3) 8
2+3*6-(1+3) 16
2+3*6-(1.3+5/2) 16.2

 

说明

  1. 自己的学习笔记 ，还有一些bug没有解决；
  2. 部分代码需要优化，重构；
  3. 没有实现输入错误表达式报错功能，需要输入正确的表达式。
  4. 不支持负数计算。
  5. 支持小数，加，减，乘，除，括号运算。

C++结合QT实现带有优先级的计算器功能

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原文链接：https://blog.csdn.net/qq_44052058/article/details/112170541

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