diff --git a/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/Lab3-1-2_Calculator4490_v4.pro b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/Lab3-1-2_Calculator4490_v4.pro
new file mode 100644
index 0000000..bc0f036
--- /dev/null
+++ b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/Lab3-1-2_Calculator4490_v4.pro
@@ -0,0 +1,26 @@
+QT       += core gui
+
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
+
+CONFIG += c++17
+
+# You can make your code fail to compile if it uses deprecated APIs.
+# In order to do so, uncomment the following line.
+#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
+
+SOURCES += \
+    cal.cpp \
+    main.cpp \
+    mainwindow.cpp
+
+HEADERS += \
+    cal.h \
+    mainwindow.h
+
+FORMS += \
+    mainwindow.ui
+
+# Default rules for deployment.
+qnx: target.path = /tmp/$${TARGET}/bin
+else: unix:!android: target.path = /opt/$${TARGET}/bin
+!isEmpty(target.path): INSTALLS += target
diff --git a/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/cal.cpp b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/cal.cpp
new file mode 100644
index 0000000..8b5f4ce
--- /dev/null
+++ b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/cal.cpp
@@ -0,0 +1,164 @@
+#include "cal.h"
+QString inToPost(QString infix) {
+  std::stack<char> stack;
+  char current = 0; //读入的字符
+  QString postfix;  //写入后缀表达式的字符串
+
+  std::map<char, int> priority; //运算符号优先级表
+  priority['+'] = 0;
+  priority['-'] = 0;
+  priority['*'] = 1;
+  priority['/'] = 1;
+  priority['^'] = 2;
+
+  for (int i = 0; i < infix.length(); ++i) //逐个读取中缀表达式字符串中的字符
+  {
+    current = infix[i].toLatin1();
+    if (isdigit(current)) //如果是数字直接输出
+    {
+      postfix.push_back(current);
+      continue;
+    }
+    switch (current) {
+    case '+':
+    case '-':
+    case '*':
+    case '/':
+    case '^':
+      // postfix.push_back('#');
+      if (i >
+          0) //如果运算符的前一项不是右括号则说明前一个数字输入完毕，用#标识前面几个字符组成一个数字
+      {
+        if (infix[i - 1] != ')')
+          postfix.push_back('#');
+        /*if(infix[i-1].isDigit())
+            postfix.push_back('#');
+        else
+            throw "expression is illegality";*/
+      } else
+        postfix.push_back('#');
+      if (!stack
+               .empty()) //比较目前符号与栈顶符号优先级，低于则出栈，并输出字符串
+      {
+        char tempTop = stack.top();
+        while (tempTop != '(' && priority[current] <= priority[tempTop]) {
+          stack.pop();
+          postfix.push_back(tempTop);
+          if (stack.empty())
+            break;
+          tempTop = stack.top();
+        }
+      }
+      stack.push(
+          current); //符号全部出栈或者遇到了'('或者大于栈顶符号的优先级，将新符号压入栈中
+      break;
+    case '.':
+      postfix.push_back(current);
+      break;
+    case '%':
+      postfix.push_back(current);
+      break;
+    case '(':
+      stack.push(current); //左括号直接入栈
+      break;
+    case ')':
+      postfix.push_back('#'); //右括号说明前方数字输入完成，标识一下
+      char tempTop;
+      tempTop = stack.top();
+      while (tempTop != '(') //直到栈顶元素是左括号才停止循环
+      {
+        stack.pop();
+        postfix.push_back(tempTop);
+        tempTop = stack.top();
+      }
+      stack.pop();
+      break;
+    default:
+      throw "expression has illegality character";
+      break;
+    }
+  }
+  if (infix[infix.size() - 1] != ')') {
+    if (infix[infix.size() - 1].isDigit())
+      postfix.push_back('#');
+    else
+      throw "expression is illegality";
+  }
+  while (!stack.empty()) {
+    char tempOut = stack.top();
+    stack.pop();
+    postfix.push_back(tempOut);
+  }
+  return postfix;
+}
+
+double compute(QString s) {
+  std::stack<double> stack;
+  QString str;
+  double curr;
+
+  double temNum1;
+  double temNum2;
+  for (auto i = s.begin(); i != s.end(); i++) {
+    if ((*i).isDigit()) {
+      str.push_back(*i);
+      continue;
+    }
+    switch ((*i).toLatin1()) {
+    case '+':
+      temNum1 = stack.top();
+      stack.pop();
+      temNum2 = stack.top();
+      stack.pop();
+      stack.push(temNum2 + temNum1);
+      break;
+    case '-':
+      temNum1 = stack.top();
+      stack.pop();
+      temNum2 = stack.top();
+      stack.pop();
+      stack.push(temNum2 - temNum1);
+      break;
+    case '*':
+      temNum1 = stack.top();
+      stack.pop();
+      temNum2 = stack.top();
+      stack.pop();
+      stack.push(temNum2 * temNum1);
+      break;
+    case '/':
+      temNum1 = stack.top();
+      stack.pop();
+      temNum2 = stack.top();
+      stack.pop();
+      stack.push(temNum2 / temNum1);
+      break;
+    case '^':
+      temNum1 = stack.top();
+      stack.pop();
+      temNum2 = stack.top();
+      stack.pop();
+      stack.push(pow(temNum2, temNum1));
+      break;
+    case '.':
+      str.push_back(*i);
+      break;
+    case '#':
+      curr = str.toDouble(); //字符串转换为浮点型
+      str.clear();
+      stack.push(curr);
+      break;
+    case '%':
+      curr = stack.top();
+      stack.pop();
+      curr *= 0.01;
+      stack.push(curr);
+      break;
+    default:
+      throw "expression has illegality character";
+      break;
+    }
+  }
+  curr = stack.top();
+  return curr;
+}
diff --git a/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/cal.h b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/cal.h
new file mode 100644
index 0000000..198fcdc
--- /dev/null
+++ b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/cal.h
@@ -0,0 +1,15 @@
+#ifndef CAL_H
+#define CAL_H
+#include "mainwindow.h"
+#include <QDebug>
+#include <QKeyEvent>
+#include <QMessageBox>
+#include <QMouseEvent>
+#include <cmath>
+#include <iostream>
+#include <map>
+#include <stack>
+
+QString inToPost(QString infix);
+double compute(QString s);
+#endif // CAL_H
diff --git a/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/main.cpp b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/main.cpp
new file mode 100644
index 0000000..fd3e533
--- /dev/null
+++ b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/main.cpp
@@ -0,0 +1,11 @@
+#include "mainwindow.h"
+
+#include <QApplication>
+
+int main(int argc, char *argv[])
+{
+    QApplication a(argc, argv);
+    MainWindow w;
+    w.show();
+    return a.exec();
+}
diff --git a/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.cpp b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.cpp
new file mode 100644
index 0000000..77a10fe
--- /dev/null
+++ b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.cpp
@@ -0,0 +1,127 @@
+#include "mainwindow.h"
+#include "cal.h"
+#include "ui_mainwindow.h"
+#include <QMessageBox>
+
+static QString displayText;
+
+MainWindow::MainWindow(QWidget *parent)
+    : QMainWindow(parent), ui(new Ui::MainWindow) {
+  ui->setupUi(this);
+  ui->lineEdit->setText("0");
+  result = 0.0;
+  waitForOperand = true;
+
+  connectSlots();
+}
+
+MainWindow::~MainWindow() { delete ui; }
+
+//错误处理
+void MainWindow::abortOperation() {
+  result = 0.0;
+  pendingOperator.clear();
+  ui->lineEdit->setText("0");
+  isFinished = false;
+  QMessageBox::warning(this, "运算错误", "算式不合法");
+}
+
+//数字被点击
+void MainWindow::digitClicked() {
+  QPushButton *digitBtn = static_cast<QPushButton *>(sender());
+  //    if(ui->lineEdit->text() == "0" && value == "0")
+  //        return;
+  if (!isFinished) {
+    displayText.append(digitBtn->text());
+    ui->lineEdit->setText(displayText);
+  } else {
+    return;
+  }
+}
+
+void MainWindow::on_clearBtn_clicked() {
+  //将当前显示的数归零
+  displayText.chop(1);
+  ui->lineEdit->setText(displayText);
+  isFinished = false;
+}
+
+void MainWindow::on_clearAllBtn_clicked() {
+  //将当前显示的数据归零，并将之前保存的数据运算清除
+  displayText.clear();
+  ui->lineEdit->setText(displayText);
+  isFinished = false;
+  result = 0.0;
+}
+
+void MainWindow::on_equalBtn_clicked() {
+  try {
+    result = compute(inToPost(ui->lineEdit->text()));
+  }
+
+  catch (...) {
+    abortOperation();
+  }
+  isFinished = 1;
+  ui->lineEdit->setText(QString::number(result));
+}
+
+//运算符
+void MainWindow::operatorClicked() {
+  QPushButton *clickedBtn = qobject_cast<QPushButton *>(sender());
+  if (!isFinished) {
+    displayText.append(clickedBtn->text());
+    ui->lineEdit->setText(displayText);
+  } else {
+    return;
+  }
+}
+
+//槽链接
+void MainWindow::connectSlots() {
+
+  QPushButton *digitBtns[10] = {ui->digitBtn0, ui->digitBtn1, ui->digitBtn2,
+                                ui->digitBtn3, ui->digitBtn4, ui->digitBtn5,
+                                ui->digitBtn6, ui->digitBtn7, ui->digitBtn8,
+                                ui->digitBtn9};
+  for (auto btn : digitBtns)
+    connect(btn, &QPushButton::clicked, this, &MainWindow::digitClicked);
+  QPushButton *operatorBtns[8] = {
+      ui->addBtn,    ui->subtractionBtn, ui->mulBtn, ui->divisionBtn,
+      ui->squareBtn, ui->pointBtn,       ui->LBtn,   ui->RBtn};
+  for (auto btn : operatorBtns)
+    connect(btn, &QPushButton::clicked, this, &MainWindow::operatorClicked);
+}
+
+void MainWindow::keyPressEvent(QKeyEvent *event) {
+  switch (event->key()) {
+  case Qt::Key_0:
+    emit ui->digitBtn0->clicked();
+    break;
+  case Qt::Key_1:
+    emit ui->digitBtn1->clicked();
+    break;
+  case Qt::Key_2:
+    emit ui->digitBtn2->clicked();
+    break;
+  case Qt::Key_3:
+    emit ui->digitBtn3->clicked();
+    break;
+  case Qt::Key_4:
+    emit ui->digitBtn4->clicked();
+    break;
+  case Qt::Key_5:
+    emit ui->digitBtn5->clicked();
+    break;
+  case Qt::Key_6:
+    emit ui->digitBtn6->clicked();
+    break;
+  case Qt::Key_7:
+    emit ui->digitBtn7->clicked();
+    break;
+  case Qt::Key_8:
+
+  default:
+    break;
+  }
+}
diff --git a/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.h b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.h
new file mode 100644
index 0000000..84efef0
--- /dev/null
+++ b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.h
@@ -0,0 +1,48 @@
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QKeyEvent>
+#include <QMainWindow>
+QT_BEGIN_NAMESPACE
+namespace Ui {
+class MainWindow;
+}
+QT_END_NAMESPACE
+
+class MainWindow : public QMainWindow {
+  Q_OBJECT
+
+public:
+  MainWindow(QWidget *parent = nullptr);
+  ~MainWindow();
+
+private:
+  Ui::MainWindow *ui;
+
+  void keyPressEvent(QKeyEvent *e);
+
+  //终止运算，清除数据，报错
+  void abortOperation();
+  //连接信号和槽
+  void connectSlots();
+  //储存运算符
+  QString pendingOperator;
+  //储存运算结果
+  double result;
+  //标记是否等待一个操作数
+  bool waitForOperand;
+
+  bool isFinished;
+
+private slots:
+  void on_clearBtn_clicked();
+
+  void on_clearAllBtn_clicked();
+
+  void on_equalBtn_clicked();
+
+  void digitClicked();
+
+  void operatorClicked();
+};
+#endif // MAINWINDOW_H
diff --git a/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.ui b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.ui
new file mode 100644
index 0000000..efd9574
--- /dev/null
+++ b/SoftwareDesign/Lab3/Lab3-1-2_Calculator4490_v4/mainwindow.ui
@@ -0,0 +1,194 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MainWindow</class>
+ <widget class="QMainWindow" name="MainWindow">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>406</width>
+    <height>362</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Calculator_v3_4490</string>
+  </property>
+  <property name="toolButtonStyle">
+   <enum>Qt::ToolButtonTextOnly</enum>
+  </property>
+  <widget class="QWidget" name="centralwidget">
+   <layout class="QGridLayout" name="gridLayout">
+    <item row="4" column="1">
+     <widget class="QPushButton" name="digitBtn8">
+      <property name="text">
+       <string>8</string>
+      </property>
+     </widget>
+    </item>
+    <item row="4" column="2">
+     <widget class="QPushButton" name="digitBtn9">
+      <property name="text">
+       <string>9</string>
+      </property>
+     </widget>
+    </item>
+    <item row="4" column="0">
+     <widget class="QPushButton" name="digitBtn7">
+      <property name="text">
+       <string>7</string>
+      </property>
+     </widget>
+    </item>
+    <item row="5" column="1">
+     <widget class="QPushButton" name="digitBtn0">
+      <property name="text">
+       <string>0</string>
+      </property>
+     </widget>
+    </item>
+    <item row="0" column="0" colspan="4">
+     <widget class="QLineEdit" name="lineEdit">
+      <property name="alignment">
+       <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
+      </property>
+      <property name="readOnly">
+       <bool>true</bool>
+      </property>
+     </widget>
+    </item>
+    <item row="2" column="3">
+     <widget class="QPushButton" name="addBtn">
+      <property name="text">
+       <string>+</string>
+      </property>
+     </widget>
+    </item>
+    <item row="5" column="3">
+     <widget class="QPushButton" name="divisionBtn">
+      <property name="text">
+       <string>/</string>
+      </property>
+     </widget>
+    </item>
+    <item row="2" column="2">
+     <widget class="QPushButton" name="digitBtn3">
+      <property name="text">
+       <string>3</string>
+      </property>
+     </widget>
+    </item>
+    <item row="2" column="1">
+     <widget class="QPushButton" name="digitBtn2">
+      <property name="text">
+       <string>2</string>
+      </property>
+     </widget>
+    </item>
+    <item row="2" column="0">
+     <widget class="QPushButton" name="digitBtn1">
+      <property name="text">
+       <string>1</string>
+      </property>
+     </widget>
+    </item>
+    <item row="4" column="3">
+     <widget class="QPushButton" name="mulBtn">
+      <property name="text">
+       <string>*</string>
+      </property>
+     </widget>
+    </item>
+    <item row="3" column="2">
+     <widget class="QPushButton" name="digitBtn6">
+      <property name="text">
+       <string>6</string>
+      </property>
+     </widget>
+    </item>
+    <item row="5" column="2">
+     <widget class="QPushButton" name="squareBtn">
+      <property name="text">
+       <string>^</string>
+      </property>
+     </widget>
+    </item>
+    <item row="3" column="1">
+     <widget class="QPushButton" name="digitBtn5">
+      <property name="text">
+       <string>5</string>
+      </property>
+     </widget>
+    </item>
+    <item row="3" column="0">
+     <widget class="QPushButton" name="digitBtn4">
+      <property name="text">
+       <string>4</string>
+      </property>
+     </widget>
+    </item>
+    <item row="5" column="0">
+     <widget class="QPushButton" name="pointBtn">
+      <property name="text">
+       <string>.</string>
+      </property>
+     </widget>
+    </item>
+    <item row="3" column="3">
+     <widget class="QPushButton" name="subtractionBtn">
+      <property name="text">
+       <string>-</string>
+      </property>
+     </widget>
+    </item>
+    <item row="6" column="2" colspan="2">
+     <widget class="QPushButton" name="equalBtn">
+      <property name="text">
+       <string>=</string>
+      </property>
+     </widget>
+    </item>
+    <item row="6" column="0">
+     <widget class="QPushButton" name="LBtn">
+      <property name="text">
+       <string>(</string>
+      </property>
+     </widget>
+    </item>
+    <item row="1" column="2" colspan="2">
+     <widget class="QPushButton" name="clearAllBtn">
+      <property name="text">
+       <string>ClearAll</string>
+      </property>
+     </widget>
+    </item>
+    <item row="1" column="0" colspan="2">
+     <widget class="QPushButton" name="clearBtn">
+      <property name="text">
+       <string>Back</string>
+      </property>
+     </widget>
+    </item>
+    <item row="6" column="1">
+     <widget class="QPushButton" name="RBtn">
+      <property name="text">
+       <string>)</string>
+      </property>
+     </widget>
+    </item>
+   </layout>
+  </widget>
+  <widget class="QMenuBar" name="menubar">
+   <property name="geometry">
+    <rect>
+     <x>0</x>
+     <y>0</y>
+     <width>406</width>
+     <height>30</height>
+    </rect>
+   </property>
+  </widget>
+  <widget class="QStatusBar" name="statusbar"/>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>