Developing Good user friendly Graphical user Interface is always a challenging task. Worse will be the case if the user interface wants to be cross platform. With the introduction of QT C++ libraries , this job is now as easy as developing a single source base and compiling it on multiple platforms. In this video tutorial, we will show you how to develop a basic QT C++ GUI application Video tutorial using an example Simple Interest.

Watch the YouTube Video from the link below ..




Main Source Code

SimpleInterest.h

#ifndef SIMPLEINTEREST_H
#define SIMPLEINTEREST_H

#include <QMainWindow>

namespace Ui {
    class SimpleInterest;
}

class SimpleInterest : public QMainWindow {
    Q_OBJECT
public:
    SimpleInterest(QWidget *parent = 0);
    ~SimpleInterest();

protected:
    void changeEvent(QEvent *e);
    void Calculate();

private:
    Ui::SimpleInterest *ui;

private slots:
    void on_pushButton_clicked();
    void on_pushButton_clicked(bool checked);
};

#endif // SIMPLEINTEREST_H

simpleinterest.cpp

#include "simpleinterest.h"
#include "ui_simpleinterest.h"
#include <QApplication>
#include "qbytearray.h"
#include <QString>

SimpleInterest::SimpleInterest(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::SimpleInterest)
{
    ui->setupUi(this);
}

SimpleInterest::~SimpleInterest()
{
    delete ui;
}

void SimpleInterest::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}



void SimpleInterest::on_pushButton_clicked()
{

Calculate();


}
void SimpleInterest::Calculate()
{
    QString Amount=ui->textAmount->toPlainText();
        QString NoofMonths=ui->textMonths->toPlainText();
        QString Interest=ui->textInterest->toPlainText();
        double InterestRate=(Amount.toDouble())+(Amount.toDouble()*NoofMonths.toDouble()*Interest.toDouble()/100);
        QString Result;
            Result.sprintf("%f",InterestRate);
            ui->textResult->setText(Result);


}

main.cpp

#include <QtGui/QApplication>
#include "simpleinterest.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    SimpleInterest w;
    w.show();
    return a.exec();
}