How to make a simple calculator in Qt
Article Metadata
Tested with
Devices(s): S60 Emulator
Compatibility
Platform(s): Qt
Article
Keywords: QLineEdit,QPushButton
Created: mind_freak
(28 Mar 2009)
Last edited: hamishwillee
(11 Oct 2012)
Contents |
Introduction
This example demonstrates a simple QWidget based calculator.
The drag and drop pattern is used to built this calculator. Several PushButton are dragged and dropped to the form and the code of click event to button is written. Specific event is triggered on pressing button.
Preconditions
- Download and install the Qt SDK.
UI design
Source code
Header File
#ifndef CALCULATOR_H
#define CALCULATOR_H
#include <QtGui/QWidget>
#include<QString>
namespace Ui
{
class calculatorClass;
}
class calculator : public QWidget
{
Q_OBJECT
public:
calculator(QWidget *parent = 0);
~calculator();
private:
Ui::calculatorClass *ui;
private:
QString str;
QString str1;
QString ch;
QString strResult;
QString text1;
public:
float num;
float num1;
float ans;
private slots:
void addi();
void subs();
void mult();
void divi();
void em();
void mone();
void mtwo();
void mthree();
void mfour();
void mfive();
void msix();
void mseven();
void meight();
void mnine();
void mzero();
void mreset();
void mon();
void moff();
void mdot();
};
#endif // CALCULATOR_H
Source code
#include "calculator.h"
#include "ui_calculator.h"
calculator::calculator(QWidget *parent)
: QWidget(parent), ui(new Ui::calculatorClass)
{
ui->setupUi(this);
text1="";
ui->line->setAlignment(Qt::AlignRight);
ui->line->setMaxLength(12);
ans=0;
QObject::connect(ui->but1,SIGNAL(clicked()),this,SLOT(addi()));
QObject::connect(ui->but2,SIGNAL(clicked()),this,SLOT(subs()));
QObject::connect(ui->but3,SIGNAL(clicked()),this,SLOT(mult()));
QObject::connect(ui->but4,SIGNAL(clicked()),this,SLOT(divi()));
QObject::connect(ui->equal,SIGNAL(clicked()),this,SLOT(em()));
QObject::connect(ui->one,SIGNAL(clicked()),this,SLOT(mone()));
QObject::connect(ui->two,SIGNAL(clicked()),this,SLOT(mtwo()));
QObject::connect(ui->three,SIGNAL(clicked()),this,SLOT(mthree()));
QObject::connect(ui->four,SIGNAL(clicked()),this,SLOT(mfour()));
QObject::connect(ui->five,SIGNAL(clicked()),this,SLOT(mfive()));
QObject::connect(ui->six,SIGNAL(clicked()),this,SLOT(msix()));
QObject::connect(ui->seven,SIGNAL(clicked()),this,SLOT(mseven()));
QObject::connect(ui->eight,SIGNAL(clicked()),this,SLOT(meight()));
QObject::connect(ui->nine,SIGNAL(clicked()),this,SLOT(mnine()));
QObject::connect(ui->zero,SIGNAL(clicked()),this,SLOT(mzero()));
QObject::connect(ui->reset,SIGNAL(clicked()),this,SLOT(mreset()));
QObject::connect(ui->on,SIGNAL(clicked()),this,SLOT(mon()));
QObject::connect(ui->off,SIGNAL(clicked()),this,SLOT(moff()));
QObject::connect(ui->dot,SIGNAL(clicked()),this,SLOT(mdot()));
}
calculator::~calculator()
{
delete ui;
}
void calculator::mdot()
{
text1+=ui->dot->text();
ui->line->setText(text1);
}
void calculator::moff()
{
ui->one->setEnabled(0);
ui->two->setEnabled(0);
ui->three->setEnabled(0);
ui->four->setEnabled(0);
ui->five->setEnabled(0);
ui->six->setEnabled(0);
ui->seven->setEnabled(0);
ui->eight->setEnabled(0);
ui->nine->setEnabled(0);
ui->zero->setEnabled(0);
ui->equal->setEnabled(0);
ui->but1->setEnabled(0);
ui->but2->setEnabled(0);
ui->but3->setEnabled(0);
ui->but4->setEnabled(0);
ui->off->setEnabled(0);
ui->reset->setEnabled(0);
ui->on->setEnabled(1);
ui->line->setEnabled(0);
ui->dot->setEnabled(0);
//ui->backspc->setEnabled(0);
ui->line->clear();
}
void calculator::mon()
{
ui->one->setEnabled(1);
ui->two->setEnabled(1);
ui->three->setEnabled(1);
ui->four->setEnabled(1);
ui->five->setEnabled(1);
ui->six->setEnabled(1);
ui->seven->setEnabled(1);
ui->eight->setEnabled(1);
ui->nine->setEnabled(1);
ui->zero->setEnabled(1);
ui->equal->setEnabled(1);
ui->but1->setEnabled(1);
ui->but2->setEnabled(1);
ui->but3->setEnabled(1);
ui->but4->setEnabled(1);
ui->off->setEnabled(1);
ui->reset->setEnabled(1);
ui->on->setEnabled(0);
ui->line->setEnabled(1);
ui->dot->setEnabled(1);
//ui->backspc->setEnabled(1);
}
void calculator::mreset()
{
text1="";
ui->line->clear();
}
void calculator::mone()
{
text1+=ui->one->text();
ui->line->setText(text1);
}
void calculator::mtwo()
{
text1+=ui->two->text();
ui->line->setText(text1);
}
void calculator::mthree()
{
text1+=ui->three->text();
ui->line->setText(text1);
}
void calculator::mfour()
{
text1+=ui->four->text();
ui->line->setText(text1);
}
void calculator::mfive()
{
text1+=ui->five->text();
ui->line->setText(text1);
}
void calculator::msix()
{
text1+=ui->six->text();
ui->line->setText(text1);
}
void calculator::mseven()
{
text1+=ui->seven->text();
ui->line->setText(text1);
}
void calculator::meight()
{
text1+=ui->eight->text();
ui->line->setText(text1);
}
void calculator::mnine()
{
text1+=ui->nine->text();
ui->line->setText(text1);
}
void calculator::mzero()
{
text1+=ui->zero->text();
ui->line->setText(text1);
}
void calculator::addi() //Addition
{
str=ui->line->text();
num=str.toFloat();
ch=ui->but1->text();
ui->line->clear();
text1="";
}
void calculator::subs() //Substraction
{
str=ui->line->text();
num=str.toFloat();
ch=ui->but2->text();
ui->line->clear();
text1="";
}
void calculator::mult() //Multiplaction
{
str=ui->line->text();
num=str.toFloat();
ch=ui->but3->text();
ui->line->clear();
text1="";
}
void calculator::divi() //Division
{
str=ui->line->text();
num=str.toFloat();
ch=ui->but4->text();
ui->line->clear();
text1="";
}
void calculator::em()
{
str1 = ui->line->text();
num1 = str1.toFloat();
if (ch=="+")
{
ans=num+num1;
}
else if(ch=="-")
{
ans=num-num1;
}
else if(ch=="*")
{
ans=num*num1;
}
else if(ch=="/")
{
ans=num/num1;
}
else
{
strResult = strResult.number(ans);
ui->line->setText(strResult);
}
strResult = strResult.number(ans);
ui->line->setText(strResult);
ch="";
text1=strResult;
}
Screenshots
Ramanrayat7 -
i have some knowledge of c++ and java .......plz advise me how to create app using qtramanrayat7 16:19, 30 April 2012 (EEST)