學Q5不久,小試牛刀，下面的截圖是Qt5 編寫的簡單計算。
下面是源碼
//calculator.h
#ifndef CALCULATOR_H
#define CALCULATOR_H
#include<QTextEdit>
#include<QPushButton>
#include<QAction>
//#include<QtWidgets>
#include<QVector>
/*
先將表達式的單個字符依次存儲到容器內，當出現“=”時，再將其
取出送入到相應的操作數容器和操作符容器為盡可能的接受用戶不
規范的輸入，設置了很多標志開關，有些亂還有bug未能解決.
*/
class Calculator : public QWidget
{
Q_OBJECT
public:
Calculator(QWidget *parent = 0);
~Calculator();
private:
QTextEdit* screenTextEdit;//表達式顯示屏
QPushButton* button1;
QPushButton* button2;
QPushButton* button3;
QPushButton* button4;
QPushButton* button5;
QPushButton* button6;
QPushButton* button7;
QPushButton* button8;
QPushButton* button9;
QPushButton* button0;
QPushButton* buttonx;// sign '*'
QPushButton* buttondivide;// sign '/'
QPushButton* buttonadd;// sign '+
QPushButton* buttonsub;// sign '-'
QPushButton* buttondot;// sign '.'
QPushButton* buttonequal;// sign '='
QPushButton* buttonclear;//清屏
QPushButton* buttonback;// backspace
QPushButton* buttonLArc;// sign '('
QPushButton* buttonRArc;// sign ')'
bool isEnter;//作為是否換行的依據,注意是光標先換行
double sum ;//臨時存放操作數
int i;//轉化成小數的除數
int j;//壓入操作數棧的開關
double result;//計算所得結果
bool isPoint;//是否出現小數點
bool isLArc;//標記是否出現（以便判斷區分出類似'（-2'形式
char sign;//用來存放符號
bool isTwoOptrsFlag;//++, -+ ...
bool isEqualClicked;//作為是否回退容器內的字符的開關
int f1[7];//棧內符號優先級
int f2[7];//棧外符號優先級
//建立操作數和操作符的棧
QVector<double>vectorOpnd;
QVector<char>vectorOptr;
QVector<char>vectorExp;
bool isTwoOptr(QPushButton *button);//++, -+ ...
void initConnect();
void initVector();
double operate(double a, char theat, double b);//進行兩個操作數的運算,返回結果
char precedeSign(char optr1, char optr2);//比較棧內和棧外符號的優先級
int char2num(char optr);//獲取符號在優先級數組中的序號
void initData();//初始化各個標志變量
char button2char(QPushButton *button);//按鈕轉化為相應符號
void getDigital(char digital);//進行數字的進棧操作
void getSign(char ch);//獲取符號
bool pickSign(char ch);//分揀符號，以便進行相應的操作
bool pushVector(char optr);//進行符號的進棧操作
void getResult();//
private slots:
void getButton();//獲取按下的按鈕
void clearScreen();//清屏
void myBackSpace();//執行backspace
};
#endif // CALCULATOR_H
//calculator.cpp
#include "calculator.h"
#include<QGridLayout>
//#include<QDebug>
Calculator::Calculator(QWidget *parent)
: QWidget(parent)
{
initData();
setWindowTitle("計算器");
setWindowIcon(QIcon(":/calculator.png"));
screenTextEdit = new QTextEdit;
screenTextEdit->setFont(QFont("Courier 10 Pitch", 18, QFont::Bold));
screenTextEdit->setReadOnly(true);
// screenTextEdit->setEnabled(false);
button1 = new QPushButton("1");
button2 = new QPushButton("2");
button3 = new QPushButton("3");
button4 = new QPushButton("4");
button5 = new QPushButton("5");
button6 = new QPushButton("6");
button7 = new QPushButton("7");
button8 = new QPushButton("8");
button9 = new QPushButton("9");
button0 = new QPushButton("0");
buttonx = new QPushButton("×");
buttonadd = new QPushButton("+");//
buttonsub = new QPushButton("-");
buttonback = new QPushButton("back");
buttondivide = new QPushButton("/");
buttondot = new QPushButton(".");
buttonLArc = new QPushButton("(");
buttonRArc = new QPushButton(")");
buttonequal = new QPushButton("=");
buttonclear = new QPushButton("clear");
initConnect();
QGridLayout *gridLayout = new QGridLayout;
gridLayout->addWidget(screenTextEdit, 0, 0, 2, 5);
gridLayout->addWidget(button1, 2, 0, 1, 1);
gridLayout->addWidget(button2, 2, 1, 1 ,1);
gridLayout->addWidget(button3, 2, 2, 1, 1);
gridLayout->addWidget(buttonadd, 2, 3, 1, 1);
gridLayout->addWidget(buttonsub, 2, 4, 1, 1);
gridLayout->addWidget(button4, 3, 0, 1, 1);
gridLayout->addWidget(button5, 3, 1, 1, 1);
gridLayout->addWidget(button6, 3, 2, 1, 1);
gridLayout->addWidget(buttonx, 3, 3, 1, 1);
gridLayout->addWidget(buttondivide, 3, 4, 1, 1);
gridLayout->addWidget(button7, 4, 0, 1, 1);
gridLayout->addWidget(button8, 4, 1, 1, 1);
gridLayout->addWidget(button9, 4, 2, 1, 1);
gridLayout->addWidget(buttonLArc, 4, 3, 1, 1);
gridLayout->addWidget(buttonRArc, 4, 4, 1, 1);
gridLayout->addWidget(button0, 5, 0, 1, 1);
gridLayout->addWidget(buttondot, 5, 1, 1, 1);
gridLayout->addWidget(buttonback, 5, 2, 1, 1);
gridLayout->addWidget(buttonclear, 5, 3, 1, 1);
gridLayout->addWidget(buttonequal, 5, 4, 1, 1);
setLayout(gridLayout);
initVector();
}
void Calculator::initConnect()
{
connect(button0, &QPushButton::clicked, this, &Calculator::getButton);
connect(button1, &QPushButton::clicked, this, &Calculator::getButton);
connect(button2, &QPushButton::clicked, this, &Calculator::getButton);
connect(button3, &QPushButton::clicked, this, &Calculator::getButton);
connect(button4, &QPushButton::clicked, this, &Calculator::getButton);
connect(button5, &QPushButton::clicked, this, &Calculator::getButton);
connect(button6, &QPushButton::clicked, this, &Calculator::getButton);
connect(button7, &QPushButton::clicked, this, &Calculator::getButton);
connect(button8, &QPushButton::clicked, this, &Calculator::getButton);
connect(button9, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttonx, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttonadd, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttondivide, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttondot, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttonsub, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttonRArc, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttonLArc, &QPushButton::clicked, this, &Calculator::getButton);
connect(buttonback, &QPushButton::clicked, this, &Calculator::myBackSpace);
connect(buttonclear, &QPushButton::clicked, this, &Calculator::clearScreen);
connect(buttonequal, &QPushButton::clicked, this, &Calculator::getButton);
}
bool Calculator::isTwoOptr(QPushButton *button)
{
if(button == buttonadd || button ==buttonsub
|| button == buttonx || button == buttondivide)
return true;
else
return false;
}
void Calculator::myBackSpace()
{
QTextCursor cursor = screenTextEdit->textCursor();
cursor.deletePreviousChar();
if(!isEqualClicked)
vectorExp.pop_back();
}
void Calculator::getButton()
{
QPushButton* button = qobject_cast<QPushButton*>(sender());
if(isTwoOptrsFlag && isTwoOptr(button))
{
}
else{
vectorExp.append(button2char(button));
isEqualClicked = false;
isTwoOptrsFlag = false;
if(!isEnter)
screenTextEdit->append("");
screenTextEdit->insertPlainText(button->text());
isEnter = true;
if(button == buttonadd || button == buttonsub
|| button == buttonx || button == buttondivide)
isTwoOptrsFlag = true;
}
if(button == buttonequal)
{
isEqualClicked = true;
getResult();
}
}
void Calculator::getResult()
{
while(!vectorExp.isEmpty())
{
char ch = vectorExp.first();
vectorExp.removeFirst();
getDigital(ch);
getSign(ch);
}
}
void Calculator::getDigital(char digital)
{
if(digital == '0' || digital == '1' || digital == '2'
|| digital == '3' || digital == '4' || digital == '5'
|| digital == '6' || digital == '7' || digital == '8'
|| digital == '9' )
{
if(isPoint)
i *= 10;//i初值是1
j = 0;//j標記是否連續字符輸入
sum = sum * 10 + (digital - '0');
isLArc = false;
}
else if(digital == '.')
{
isPoint = true;
isLArc = false;
}
}
void Calculator::getSign(char ch)
{
if(isLArc && ch != '(' && ch != ')')
{
sign = ch;
}
else if(ch == '+' || ch == '-'
|| ch == '*' || ch == '/'
|| ch == '=' || ch == '('
|| ch == ')')
{
if(ch == '(')
isLArc = true;
else
isLArc = false;
j++;
if(j <=1)
{
if(sign == '-')
sum = sum * (-1);
sign = ' ';
vectorOpnd.append(sum / i);
isLArc = false;
i = 1;
sum = 0;
isPoint = false;
}
pickSign(ch);
}
}
bool Calculator::pickSign(char ch)
{
char theta;
double a, b;
if(ch == '=')
{
while(vectorOptr.last() != '#')
{
do{
theta = vectorOptr.last();
vectorOptr.pop_back();
}while(theta == '(' || theta == ')');
if(theta != '#')//void 8(,9),8()
{
b = vectorOpnd.last();vectorOpnd.pop_back();
a = vectorOpnd.last();vectorOpnd.pop_back();
vectorOpnd.append(operate(a, theta, b));
}
else if(theta == '#')
vectorOptr.append('#');
}
result = vectorOpnd.last();
screenTextEdit->insertPlainText(QString("%1").arg(result));
vectorOpnd.clear();
vectorOptr.clear();
initVector();
isEnter = false;
return true;
}
pushVector(ch);
return true;
}
bool Calculator::pushVector(char optr)
{
char theta;
double a, b;
if(optr == ')')
{
do{
theta = vectorOptr.last();
vectorOptr.pop_back();
}while(theta == '(' || theta == ')');
if(theta != '#')// void 8(,9),8()
{
b = vectorOpnd.last();vectorOpnd.pop_back();
a = vectorOpnd.last();vectorOpnd.pop_back();
vectorOpnd.append(operate(a, theta, b));
}
else
{
vectorOptr.append('#');
}
return true;
}
switch(precedeSign(vectorOptr.last(),optr))
{
case '<':
vectorOptr.append(optr);
break;
case '=':
vectorOptr.pop_back();
break;
case '>':
theta = vectorOptr.last();
vectorOptr.pop_back();
b = vectorOpnd.last();
vectorOpnd.pop_back();
a = vectorOpnd.last();
vectorOpnd.pop_back();
vectorOpnd.append(operate(a, theta, b));
vectorOptr.append(optr);
break;
}
return true;
}
void Calculator::clearScreen()
{
screenTextEdit->clear();
result = 0;
isEnter = true;
}
double Calculator::operate(double a, char theta, double b)
{
double sum1;
switch (theta) {
case '+':
sum1 = a + b; break;
case '-':
sum1 = a - b; break;
case '*':
sum1 = a * b; break;
case '/':
sum1 = a / b; break;
}
return sum1;
}
char Calculator::button2char(QPushButton *button)
{
char optr;
if(button == buttonadd)
optr = '+';
else if(button == buttonsub)
optr = '-';
else if(button == buttonx)
optr = '*';
else if(button == buttondivide)
optr = '/';
else if(button == buttonLArc)
optr = '(';
else if(button == buttonRArc)
optr = ')';
else if(button == buttonequal)
optr = '=';
else if(button == button0)
optr = '0';
else if(button == button1)
optr = '1';
else if(button == button2)
optr = '2';
else if(button == button3)
optr = '3';
else if(button == button4)
optr = '4';
else if(button == button5)
optr = '5';
else if(button == button6)
optr = '6';
else if(button == button7)
optr = '7';
else if(button == button8)
optr = '8';
else if(button == button9)
optr = '9';
else if(button == buttondot)
optr = '.';
return optr;
}
char Calculator::precedeSign(char optr1, char optr2)
{
char compare;
int i1 = char2num(optr1);
int i2 = char2num(optr2);
if(f1[i1] > f2[i2])
compare = '>';
else if(f1[i1] < f2[i2])
compare = '<';
else
compare = '=';
return compare;
}
int Calculator::char2num(char optr)
{
int ii;
switch(optr)
{
case '+':
ii = 0; break;
case '-':
ii = 1; break;
case '*':
ii = 2; break;
case '/':
ii = 3; break;
case '(':
ii = 4; break;
case ')':
ii = 5; break;
default:
ii = 6;
}
return ii;
}
void Calculator::initData()
{
i = 1;
j = 0;
sum = 0;
f1[0] = f1[1] =3; f1[2] = f1[3] = 5; f1[4] = 1;
f1[5] = 6; f1[6] = 0;
f2[0] = f2[1] = 2; f2[2] = f2[3] = 4; f2[4] = 6;
f2[5] = 1; f2[6] = 0;
isPoint = false;
isLArc = false;
sign = ' ';
isTwoOptrsFlag = false;
isEqualClicked = false;
isEnter = true;
}
void Calculator::initVector()
{
vectorOptr.append('#');
vectorOpnd.append(0);
vectorOpnd.append(0);
vectorOpnd.append(0);
}
Calculator::~Calculator()
{
}
//main.cpp
#include "calculator.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Calculator cal;
cal.show();
return a.exec();
}