Qt学习（5)——写一下简单的计算器
可以执行+-*/浮点运算，直接上代码了
信号和槽的简单运用；
思路：先将字符串转化成浮点数和符号；再将中缀表达式转化为逆波兰式；最后直接计算。
Calculate.pro
#-------------------------------------------------
#
# Project created by QtCreator 2018-09-15T16:53:19
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = Calculator
TEMPLATE = app
# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
main.cpp \
mainwindow.cpp
HEADERS += \
mainwindow.h \
floatnumber.h
CONFIG += C++11
Headers:
floatnumber.h
#ifndef FLOATNUMBER_H
#define FLOATNUMBER_H
#endif // FLOATNUMBER_H
#include
using namespace std;
struct node{
int flag;
union{
double a; //flag==0
char op; //flag==1
}num;
};
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include
#include
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
~MainWindow();
void calculate();
int process(char a, char b);
private:
QString s;
//QStack num;
//stack operation;
};
#endif // MAINWINDOW_H
Sources:
main.cpp
#include "mainwindow.h"
#include
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
mainwindows.cpp
#include "mainwindow.h"
#include
#include
#include
#include
#include "floatnumber.h"
typedef struct node _tNode;
#define NUM_OF_NUMBER 20
#define KIND_NUMBER 0
#define KIND_OPERATOR 1
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
//初始化
s = "";
resize(510,510);
setWindowTitle("计算器");
//设置按钮,指定父对象
QPushButton *button_1 = new QPushButton(this);
QPushButton *button_2 = new QPushButton(this);
QPushButton *button_3 = new QPushButton(this);
QPushButton *button_4 = new QPushButton(this);
QPushButton *button_5 = new QPushButton(this);
QPushButton *button_6 = new QPushButton(this);
QPushButton *button_7 = new QPushButton(this);
QPushButton *button_8 = new QPushButton(this);
QPushButton *button_9 = new QPushButton(this);
QPushButton *button_0 = new QPushButton(this);
QPushButton *button_add = new QPushButton(this);
QPushButton *button_dec = new QPushButton(this);
QPushButton *button_mul = new QPushButton(this);
QPushButton *button_div = new QPushButton(this);
QPushButton *button_clear = new QPushButton(this);
QPushButton *button_equal = new QPushButton(this);
QPushButton *button_point = new QPushButton(this);
QPushButton *button_left = new QPushButton(this);
QPushButton *button_right = new QPushButton(this);
QPushButton *button_delete = new QPushButton(this);
button_0->setText("0");
button_1->setText("1");
button_2->setText("2");
button_3->setText("3");
button_4->setText("4");
button_5->setText("5");
button_6->setText("6");
button_7->setText("7");
button_8->setText("8");
button_9->setText("9");
button_add->setText("+");
button_dec->setText("-");
button_mul->setText("*");
button_div->setText("/");
button_clear->setText("CE");
button_equal->setText("=");
button_point->setText(".");
button_left->setText("(");
button_right->setText(")");
button_delete->setText("Del");
//设置显示窗口
QTextEdit *text = new QTextEdit(this);
text->resize(490,90);
text->move(10,10);
//布局
button_0->resize(90,90);
button_0->move(10,110);
button_1->resize(90,90);
button_1->move(110,110);
button_2->resize(90,90);
button_2->move(210,110);
button_3->resize(90,90);
button_3->move(310,110);
button_4->resize(90,90);
button_4->move(10,210);
button_5->resize(90,90);
button_5->move(110,210);
button_6->resize(90,90);
button_6->move(210,210);
button_7->resize(90,90);
button_7->move(310,210);
button_8->resize(90,90);
button_8->move(10,310);
button_9->resize(90,90);
button_9->move(110,310);
button_add->resize(90,90);
button_add->move(210,310);
button_dec->resize(90,90);
button_dec->move(310,310);
button_mul->resize(90,90);
button_mul->move(10,410);
button_div->resize(90,90);
button_div->move(110,410);
button_clear->resize(90,90);
button_clear->move(210,410);
button_equal->resize(90,90);
button_equal->move(310,410);
button_left->resize(90,90);
button_left->move(410,110);
button_right->resize(90,90);
button_right->move(410,210);
button_point->resize(90,90);
button_point->move(410,310);
button_delete->resize(90,90);
button_delete->move(410,410);
//连接、处理信号,lambda表达式
connect(button_0,&QPushButton::clicked,
[=]()
{
//button_0->setText("123");
s+="0";
text->setText(s);
}
);
connect(button_1,&QPushButton::clicked,
[=]()
{
s+="1";
text->setText(s);
}
);
connect(button_2,&QPushButton::clicked,
[=]()
{
s+="2";
text->setText(s);
}
);
connect(button_3,&QPushButton::clicked,
[=]()
{
s+="3";
text->setText(s);
}
);
connect(button_4,&QPushButton::clicked,
[=]()
{
s+="4";
text->setText(s);
}
);
connect(button_5,&QPushButton::clicked,
[=]()
{
s+="5";
text->setText(s);
}
);
connect(button_6,&QPushButton::clicked,
[=]()
{
s+="6";
text->setText(s);
}
);
connect(button_7,&QPushButton::clicked,
[=]()
{
s+="7";
text->setText(s);
}
);
connect(button_8,&QPushButton::clicked,
[=]()
{
s+="8";
text->setText(s);
}
);
connect(button_9,&QPushButton::clicked,
[=]()
{
s+="9";
text->setText(s);
}
);
connect(button_add,&QPushButton::clicked,
[=]()
{
s+="+";
text->setText(s);
}
);
connect(button_dec,&QPushButton::clicked,
[=]()
{
s+="-";
text->setText(s);
}
);
connect(button_mul,&QPushButton::clicked,
[=]()
{
s+="*";
text->setText(s);
}
);
connect(button_div,&QPushButton::clicked,
[=]()
{
s+="/";
text->setText(s);
}
);
connect(button_clear,&QPushButton::clicked,
[=]()
{
s="";
text->setText(s);
}
);
connect(button_left,&QPushButton::clicked,
[=]()
{
s+="(";
text->setText(s);
}
);
connect(button_right,&QPushButton::clicked,
[=]()
{
s+=")";
text->setText(s);
}
);
connect(button_point,&QPushButton::clicked,
[=]()
{
s+=".";
text->setText(s);
}
);
connect(button_delete,&QPushButton::clicked,
[=]()
{
s=s.left(s.length()-1);
text->setText(s);
}
);
// connect(button_equal,&QPushButton::clicked,
// this,
// &MainWindow::calculate
// );
connect(button_equal,&QPushButton::clicked,
[=]()
{
MainWindow::calculate();
text->setText(s);
}
);
//槽函数，由于使用lambda表达式简便书写，多数实现
}
MainWindow::~MainWindow()
{
}
void MainWindow::calculate()
{
//qDebug() << "Ready";
//QString _s;
//qDebug() << s[0];
_tNode Node[NUM_OF_NUMBER];
double num1=0;
int len=s.length();
int i=0; //字符串位置
int num_of_point=0; //小数点个数
int num_or_op=0; //浮点数和操作符的个数
int isfloat=0; //小数点
while(i='0'&&s[i]<='9')){
if(!isfloat){ //整数部分
num1=num1*10+(s[i].toLatin1()-'0');
++i;
}
else{ //小数部分
double per=1;
for(int k=0;k pNode;
_tNode _Node[NUM_OF_NUMBER];
int j = 0;
for(int i = 0; i < num_or_op;){
if(Node[i].flag){//符号
if(pNode.isEmpty())
pNode.push_back(Node[i++]);
else{
_tNode tem=pNode.top();
int ret=process(tem.num.op,Node[i].num.op);
switch (ret) {
case -1:
pNode.push_back(Node[i++]);
break;
case 1:
_Node[j++]=pNode.top();
pNode.pop();
//pNode.push_back(Node[i]);
break;
default:
pNode.pop();
i++;
break;
}
}
}
else{
_Node[j++]=Node[i++];
}
}
for(;!pNode.isEmpty();){
_tNode tem=pNode.top();
if(tem.num.op != '('&& tem.num.op != ')')
_Node[j++]=tem;
pNode.pop();
}
// for(int i=0;i<=j;i++)
// if(_Node[i].flag)
// qDebug() << _Node[i].num.op;
// else
// qDebug() << _Node[i].num.a;
//具体计算过程：
QStack last;
double d1,d2;
for(int i = 0; i < j; i++){
if(_Node[i].flag){//操作符
d2=last.top();
last.pop();
d1=last.top();
last.pop();
switch (_Node[i].num.op) {
case '+':
d1+=d2;
break;
case '-':
d1-=d2;
break;
case '*':
d1*=d2;
break;
case '/':
d1/=d2;
break;
default:
break;
}
last.push_back(d1);
}
else{
last.push_back(_Node[i].num.a);
}
}
qDebug() << d1;
s += '=';
s += QString::number(d1);
}
int MainWindow::process(char a, char b)
{
char aim[7][8] = { { ">><<<>>" },{ ">><<<>>" },{ ">>>><>>" },{ ">>>><>>" },{ "<<<<<=1" },{ ">>>>1>>" },{ "<<<<<1=" } };
char sta[7] = { '+','-','*','/','(',')','#' };
char _result;
int i, pa, pb;
for (i = 0; i<6; i++) {
if (a == sta[i])pa = i;
if (b == sta[i])pb = i;
}
_result = aim[pa][pb];
if (_result == '>')return 1;
else if (_result == '<')return -1;
else return 0;
}