代码

MyCalculator.h

#pragma once#include <QtWidgets/QMainWindow>#include <QStack>#include <QString>#include "ui_MyCalculator.h"class MyCalculator : public QMainWindow{ Q_OBJECTpublic: MyCalculator(QWidget *parent = Q_NULLPTR); 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();private: Ui::MyCalculatorClass ui;};

MyCalculator.main

#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

#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())); }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

自己的学习笔记 ，还有一些bug没有解决；

部分代码需要优化，重构；

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。

不支持负数计算。

支持小数，加，减，乘，除，括号运算。

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