要求：使用QT完成计算器UI设计，如下图：

程序运行结果：

 

代码：

 mainwindow.ui

<?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>540</width><height>960</height></rect></property><property name="windowTitle"><string>计算器</string></property><widget class="QWidget" name="centralwidget"><layout class="QVBoxLayout" name="verticalLayout_3" stretch="2,1,1,1,1,2"><item><widget class="QLabel" name="label"><property name="sizePolicy"><sizepolicy hsizetype="Preferred" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="layoutDirection"><enum>Qt::LeftToRight</enum></property><property name="text"><string>=</string></property></widget></item><item><layout class="QHBoxLayout" name="horizontalLayout"><item><widget class="QPushButton" name="pushButton_4"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>MC</string></property></widget></item><item><widget class="QPushButton" name="pushButton_3"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>MR</string></property></widget></item><item><widget class="QPushButton" name="pushButton_2"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>MS</string></property></widget></item><item><widget class="QPushButton" name="pushButton_5"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>M+</string></property></widget></item><item><widget class="QPushButton" name="pushButton"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>M-</string></property></widget></item></layout></item><item><layout class="QHBoxLayout" name="horizontalLayout_2"><item><widget class="QPushButton" name="pushButton_6"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>←</string></property></widget></item><item><widget class="QPushButton" name="pushButton_7"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>CE</string></property></widget></item><item><widget class="QPushButton" name="pushButton_8"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>C</string></property></widget></item><item><widget class="QPushButton" name="pushButton_9"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>±</string></property></widget></item><item><widget class="QPushButton" name="pushButton_10"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>√</string></property></widget></item></layout></item><item><layout class="QHBoxLayout" name="horizontalLayout_3"><item><widget class="QPushButton" name="pushButton_11"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>7</string></property></widget></item><item><widget class="QPushButton" name="pushButton_12"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>8</string></property></widget></item><item><widget class="QPushButton" name="pushButton_13"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>9</string></property></widget></item><item><widget class="QPushButton" name="pushButton_14"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>/</string></property></widget></item><item><widget class="QPushButton" name="pushButton_15"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>%</string></property></widget></item></layout></item><item><layout class="QHBoxLayout" name="horizontalLayout_4"><property name="topMargin"><number>0</number></property><item><widget class="QPushButton" name="pushButton_16"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>4</string></property></widget></item><item><widget class="QPushButton" name="pushButton_17"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>5</string></property></widget></item><item><widget class="QPushButton" name="pushButton_18"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>6</string></property></widget></item><item><widget class="QPushButton" name="pushButton_19"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>*</string></property></widget></item><item><widget class="QPushButton" name="pushButton_20"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>1/x</string></property></widget></item></layout></item><item><layout class="QHBoxLayout" name="horizontalLayout_5" stretch="2,2,1"><property name="spacing"><number>6</number></property><item><layout class="QVBoxLayout" name="verticalLayout_2"><property name="rightMargin"><number>0</number></property><item><layout class="QHBoxLayout" name="horizontalLayout_13" stretch="0,0"><property name="rightMargin"><number>0</number></property><item><widget class="QPushButton" name="pushButton_35"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>1</string></property></widget></item><item><widget class="QPushButton" name="pushButton_34"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>2</string></property></widget></item></layout></item><item><widget class="QPushButton" name="pushButton_36"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>0</string></property></widget></item></layout></item><item><layout class="QVBoxLayout" name="verticalLayout"><property name="rightMargin"><number>0</number></property><item><layout class="QHBoxLayout" name="horizontalLayout_7" stretch="0,0"><property name="spacing"><number>6</number></property><property name="leftMargin"><number>0</number></property><property name="rightMargin"><number>0</number></property><item><widget class="QPushButton" name="pushButton_23"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>3</string></property></widget></item><item><widget class="QPushButton" name="pushButton_22"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>－</string></property></widget></item></layout></item><item><layout class="QHBoxLayout" name="horizontalLayout_12"><property name="spacing"><number>6</number></property><property name="leftMargin"><number>0</number></property><property name="rightMargin"><number>0</number></property><item><widget class="QPushButton" name="pushButton_32"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>.</string></property></widget></item><item><widget class="QPushButton" name="pushButton_33"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>+</string></property></widget></item></layout></item></layout></item><item><widget class="QPushButton" name="pushButton_21"><property name="sizePolicy"><sizepolicy hsizetype="Minimum" vsizetype="Expanding"><horstretch>0</horstretch><verstretch>0</verstretch></sizepolicy></property><property name="text"><string>＝</string></property></widget></item></layout></item></layout></widget><widget class="QMenuBar" name="menubar"><property name="geometry"><rect><x>0</x><y>0</y><width>540</width><height>28</height></rect></property><widget class="QMenu" name="menuview"><property name="title"><string>查看(V)</string></property></widget><widget class="QMenu" name="menuedit"><property name="title"><string>编辑(E)</string></property></widget><widget class="QMenu" name="menuhelp"><property name="title"><string>帮助(H)</string></property></widget><addaction name="menuview"/><addaction name="menuedit"/><addaction name="menuhelp"/></widget><widget class="QStatusBar" name="statusbar"/></widget><resources/><connections/>
</ui>