用Qt写的一个简单的计算器

软件设计课也上了3、4次了，感觉自己什么都没做，感觉这门课纯属扯淡。明天就是周一了，无论怎么着也该交出点东西了，于是就趁今天周末花费了大半天写出了一个计算器，算是给自己一个交代吧。

widget.h：

 

/* * Copyright (C) 2011 @HIT Footoo Lab * Author:shiyanhui * Create Date: 2011-3-20 */#ifndef WIDGET_H#define WIDGET_H#include <QWidget>class QString ;class QLineEdit ;class QPushButton ;class QHBoxLayout ;class QVBoxLayout ;class Widget : public QWidget{ Q_OBJECTpublic: Widget( QWidget *parent = 0 ) ;private slots: void pushOperatorButton() ; void pushNumberButton() ; void pushBracketButton() ; void pushClearButton() ;private: void declareVariables() ; void createLayout() ; void createConnect() ; QLineEdit *expressionLineEdit ; QPushButton *numberPushButtons[ 10 ] ; QPushButton *bracketPushButtons[ 2 ] ; QPushButton *operatorPushButtons[ 5 ] ; QPushButton *clearPushButton ; //for left down row pushbuttons QHBoxLayout *leftDownRowLayout[ 4 ] ; //for right down row pushbuttons QHBoxLayout *rightDownRowLayout[ 3 ] ; //for left layout QVBoxLayout *leftDownLayout ; //for right layout QVBoxLayout *rightDownLayout ; //for down layout QHBoxLayout *downLayout ; //for up layout QHBoxLayout *upLayout ; //for global layout QVBoxLayout *globalLayout ;};#endif // WIDGET_H

widget.cpp：

/* * Copyright (C) 2011 @HIT Footoo Lab * Author:shiyanhui * Create Date: 2011-3-20 */#include "calculate.h"#include "widget.h"#include <QtGui>Widget::Widget(QWidget *parent) : QWidget(parent){ declareVariables() ; createLayout() ; createConnect() ;}void Widget::pushOperatorButton( ){ QPushButton *aPushButton = dynamic_cast<QPushButton*>( sender() ) ; for( int i = 0 ; i < 4 ; ++ i ) { if( aPushButton == operatorPushButtons[ i ] ) { expressionLineEdit->insert( aPushButton->text() ) ; return ; } } Calculation aCalculation( expressionLineEdit->text().toStdString() ) ; aCalculation.midfix_to_suffix( ) ; aCalculation.calculate( ) ; expressionLineEdit->setText( QString( "%1" ).arg( aCalculation.get_answer() ) ) ;}void Widget::pushNumberButton( ){ QPushButton *aPushButton = dynamic_cast<QPushButton*>( sender() ) ; for( int i = 0 ; i < 10 ; ++ i ) { if( aPushButton == numberPushButtons[ i ] ) expressionLineEdit->insert( QString( "%1" ).arg( i ) ) ; }}void Widget::pushBracketButton( ){ QPushButton *aPushButton = dynamic_cast<QPushButton*>( sender() ) ; for( int i = 0 ; i < 2 ; ++ i ) { if( aPushButton == bracketPushButtons[ i ] ) expressionLineEdit->insert( aPushButton->text() ) ; }}void Widget::pushClearButton(){ expressionLineEdit->clear() ;}void Widget::declareVariables(){ //declare lineEdit of expression expressionLineEdit = new QLineEdit() ; //declare number pushbuttons for( int i = 0 ; i < 10 ; ++ i ) { numberPushButtons[ i ] = new QPushButton( QString( "%1").arg( i ) ) ; numberPushButtons[ i ]->setDefault( true ) ; } //declare brackets pushbuttons const QString brackets[ 2 ] = { "(" , ")" } ; for( int i = 0 ; i < 2 ; ++ i ) { bracketPushButtons[ i ] = new QPushButton( brackets[ i ] ) ; } //declare operator pushbuttons const QString operators[ 5 ] = { "+" , "-" , "*" , "/" , "=" } ; for( int i = 0 ; i < 5 ; i ++ ) { operatorPushButtons[ i ] = new QPushButton( operators[ i ] ) ; } //declare clear pushbutton clearPushButton = new QPushButton( "clear" ) ; //declare layout upLayout = new QHBoxLayout ; downLayout = new QHBoxLayout ; //declare leftdown row layout for( int i = 0 ; i < 4 ; i ++ ) { leftDownRowLayout[ i ] = new QHBoxLayout ; } leftDownLayout = new QVBoxLayout ; //declare rightdown row layout for( int i = 0 ; i < 3 ; i ++ ) { rightDownRowLayout[ i ] = new QHBoxLayout ; } rightDownLayout = new QVBoxLayout ; globalLayout = new QVBoxLayout ;}//built the connectvoid Widget::createConnect(){ for( int i = 0 ; i < 10 ; ++ i ) { QObject::connect( numberPushButtons[ i ] , SIGNAL( clicked() ) , this , SLOT( pushNumberButton() ) ) ; } for( int i = 0 ; i < 5 ; ++ i ) { QObject::connect( operatorPushButtons[ i ] , SIGNAL( clicked() ) , this , SLOT( pushOperatorButton() ) ) ; } for( int i = 0 ; i < 2 ; ++ i ) { QObject::connect( bracketPushButtons[ i ] , SIGNAL( clicked() ) , this , SLOT( pushBracketButton() ) ) ; } QObject::connect( clearPushButton , SIGNAL( clicked() ) , this , SLOT( pushClearButton() ) ) ;}void Widget::createLayout(){ upLayout->addWidget( expressionLineEdit ) ; //left down const int num1[ 3 ] = { 7 , 4 , 1 } ; for( int i = 0 ; i < 3 ; ++ i ) { for( int j = 0 ; j < 3 ; ++ j ) { leftDownRowLayout[ i ]->addWidget( numberPushButtons[ j + num1[ i ] ] ) ; } } leftDownRowLayout[ 3 ]->addWidget( numberPushButtons[ 0 ] ) ; leftDownRowLayout[ 3 ]->addWidget( bracketPushButtons[ 0 ] ) ; leftDownRowLayout[ 3 ]->addWidget( bracketPushButtons[ 1 ] ) ; for( int i = 0 ; i < 4 ; ++ i ) { leftDownLayout->addLayout( leftDownRowLayout[ i ] ) ; } //right down const int num2[ 2 ] = { 0 , 2 } ; for( int i = 0 ; i < 2 ; ++ i ) { for( int j = 0 ; j < 2 ; ++ j ) { rightDownRowLayout[ i ]->addWidget( operatorPushButtons[ j + num2[ i ] ] ) ; } } rightDownRowLayout[ 2 ]->addWidget( operatorPushButtons[ 4 ] ) ; rightDownRowLayout[ 2 ]->addWidget( clearPushButton ) ; for( int i = 0 ; i < 3 ; ++ i ) { rightDownLayout->addLayout(( rightDownRowLayout[ i ] ) ) ; } downLayout->addLayout( leftDownLayout ) ; downLayout->addStretch() ; downLayout->addLayout( rightDownLayout ) ; globalLayout->addLayout( upLayout ) ; globalLayout->addLayout( downLayout ) ; this->setLayout( globalLayout ) ;}

calculate.h：

/* * Copyright (C) 2011 @HIT Footoo Lab * Author:shiyanhui * Create Date: 2011-3-20 */#ifndef CALCULATE_H#define CALCULATE_H#include<string>#include<sstream>#include<map>#define STACK_SIZE 100using namespace std ;struct CharStack{ int size ; char element[ STACK_SIZE ] ;};struct IntStack{ int size ; int element[ STACK_SIZE ] ;};class Calculation{public: //构造函数 Calculation( string ) ; //中缀表达式转换为后缀表达式 void midfix_to_suffix() ; //计算 void calculate() ; //得到结果 int get_answer() ;private: string expression ; //表达式 int answer ; //result CharStack operator_stack ; //存储操作符 IntStack operand_stack ; //存储操作数 stringstream ss ; map< char , int > aMap ; //操作符到优先级的映射};#endif

calculate.cpp：

/* * Copyright (C) 2011 @HIT Footoo Lab * Author:shiyanhui * Create Date: 2011-3-20 */#include"calculate.h"Calculation::Calculation( string expression ){ this->expression = expression ; answer = 0 ; operator_stack.size = operand_stack.size = 0 ; aMap[ 'C' ] = 0 ; aMap[ '+' ] = aMap[ '-' ] = 1 ; aMap[ '*' ] = aMap[ '/' ] = 2 ;}void Calculation::midfix_to_suffix( ){ string tmp = "" ; //将表达式扫描一遍 for( int i = 0 ; i < expression.size( ) ; ) { //如果字符是数字，继续循环下去，直到把这个数字找全，最后，在数字后面加一个'.'，以和别的数字区分开 if( isdigit( expression[ i ] ) ) { while( i < expression.size( ) ) { if( isdigit( expression[ i ] ) ) { tmp += expression[ i++ ] ; } else break ; } tmp += '.' ; } //如果是空格，ignore else if( expression[ i ] == ' ' ) { i++ ; continue ; } //其他的只能是操作符 else { if( expression[ i ] == '(' ) { operator_stack.element[ operator_stack.size++ ] = '(' ; i++ ; } else if( expression[ i ] == ')' ) { while( operator_stack.element[ operator_stack.size - 1 ] != '(' ) { tmp += operator_stack.element[ --operator_stack.size ] ; } operator_stack.size-- ; i++ ; } else { while( operator_stack.size > 0 ) { if( aMap[ expression[ i ] ] <= aMap[ operator_stack.element[ operator_stack.size - 1 ] ] ) { tmp += operator_stack.element[ --operator_stack.size ] ; } else break ; } operator_stack.element[ operator_stack.size++ ] = expression[ i++ ] ; } } } while( operator_stack.size > 0 ) { tmp += operator_stack.element[ --operator_stack.size ] ; } expression = tmp ;}void Calculation::calculate( ){ int a = 0 , b = 0 , num = 0 ; for( int i = 0 ; i < expression.size( ) ; ) { if( isdigit( expression[ i ] ) ) { string tmp = "" ; while( expression[ i ] != '.' ) { tmp += expression[ i++ ] ; } i++ ; ss << tmp ; ss >> num ; ss.clear( ) ; operand_stack.element[ operand_stack.size++ ] = num ; } else { b = operand_stack.element[ --operand_stack.size ] ; a = operand_stack.element[ --operand_stack.size ] ; switch( expression[ i ] ) { case '+': operand_stack.element[ operand_stack.size++ ] = a + b ; break ; case '-': operand_stack.element[ operand_stack.size++ ] = a - b ; break ; case '*': operand_stack.element[ operand_stack.size++ ] = a * b ; break ; case '/': operand_stack.element[ operand_stack.size++ ] = a * 1.0 / b ; } i++ ; } } answer = operand_stack.element[ 0 ] ;}int Calculation::get_answer( ){ return answer ;}

main.cpp：

/* * Copyright (C) 2011 @HIT Footoo Lab * Author:shiyanhui * Create Date: 2011-3-20 */#include <QtGui/QApplication>#include "widget.h"int main(int argc, char *argv[]){ QApplication a(argc, argv); Widget w; w.show(); return a.exec();}

来张截图吧：

 

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