How to display an LCD with a counter

[rookee]

Hello All,

I'm learning Qt using C++, a beginner. Trying to create LCD that starts counting from 0(zero) after execution, I want to incorporate a stop button to stop the counting when it is pressed and also want to incorporate a slider to increase or decrease the speed of counter. I want to use programming instead of UI/drag and drop functionality. This is just a start up I haven't included stop and slider yet. Can someone please guide me through this. Please!!!. Thanks in advance.

Code in my LCD3.h

#ifndef LCD3_H
#define LCD3_H
#include <QApplication>
#include <QLCDNumber>
#include <QWidget>
 
class ClassA: public QWidget
{
    Q_OBJECT
 
public:
    ClassA():
    number(0)
    {};
    ~ ClassA(){};
 
    void mylcd(ClassA *window)
    {
        QWidget *centralWidget = new QWidget(window);
        LCD = new QLCDNumber(centralWidget);
        window ->setCentralWidget(centralWidget);
        window->show();
        LCD->display(number ++);
    }
public slots:
    void setNumber()
    {
        if(number>=51)
        {
            timer->stop();
        }
        else
        {
            LCD->display(number++);
        }
    }
public:
            QLCDNumber *LCD;
            int number;
 
};
 
#endif // LCD3_H

#ifndef LCD3_H
#define LCD3_H
#include <QApplication>
#include <QLCDNumber>
#include <QWidget>

class ClassA: public QWidget
{
    Q_OBJECT

public:
    ClassA():
    number(0)
    {};
    ~ ClassA(){};

    void mylcd(ClassA *window)
    {
        QWidget *centralWidget = new QWidget(window);
        LCD = new QLCDNumber(centralWidget);
        window ->setCentralWidget(centralWidget);
        window->show();
        LCD->display(number ++);
    }
public slots:
    void setNumber()
    {
        if(number>=51)
        {
            timer->stop();
        }
        else
        {
            LCD->display(number++);
        }
    }
public:
            QLCDNumber *LCD;
            int number;

};

#endif // LCD3_H

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Code in my main.cpp file

#include <QApplication>
#include "LCD3.h"
#include <QLCDNumber>
 
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
    ClassA *window = new Test();
    window->setWindowTitle(QString::fromUtf8("LCD Display"));
    window->resize(300,300);
 
    ClassA win;
    win.mylcd(window);
 
    return a.exec();
};

#include <QApplication>
#include "LCD3.h"
#include <QLCDNumber>


int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    ClassA *window = new Test();
    window->setWindowTitle(QString::fromUtf8("LCD Display"));
    window->resize(300,300);

    ClassA win;
    win.mylcd(window);

    return a.exec();
};

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Is there a way that we can run the program in debug mode. Executing the code line by line and see what's happening on each line.



Here are the errors I get when I execute it.

/Qt Practice/LCD3/LCD3/LCD3.h:-1: In member function 'void ClassA::mylcd(ClassA*)':
/Qt Practice/LCD3/LCD3/LCD3.h:24: error: 'class ClassA' has no member named 'setCentralWidget'
/Qt Practice/LCD3/LCD3/LCD3.h:-1: In member function 'void ClassA::setNumber()':
/Qt Practice/LCD3/LCD3/LCD3.h:33: error: 'timer' was not declared in this scope
/Qt Practice/LCD3/LCD3/main.cpp:-1: In function 'int main(int, char**)':
/Qt Practice/LCD3/LCD3/main.cpp:10: error: expected type-specifier before 'Test'
/Qt Practice/LCD3/LCD3/main.cpp:10: error: cannot convert 'int*' to 'ClassA*' in initialization
/Qt Practice/LCD3/LCD3/main.cpp:10: error: expected ',' or ';' before 'Test'

[west]

Please

write code like this text

write code like this text

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[anda_skoa]

/Qt Practice/LCD3/LCD3/LCD3.h:-1: In member function 'void ClassA::mylcd(ClassA*)':
/Qt Practice/LCD3/LCD3/LCD3.h:24: error: 'class ClassA' has no member named 'setCentralWidget'

That means your class "ClassA" does not have a method called "setCentralWidget".
It indeed doesn't but you try to use it.

/Qt Practice/LCD3/LCD3/LCD3.h:-1: In member function 'void ClassA::setNumber()':
/Qt Practice/LCD3/LCD3/LCD3.h:33: error: 'timer' was not declared in this scope

This means your class "ClassA" does not have a member variable called "timer".
It indeed doesn't but you try to use it.

/Qt Practice/LCD3/LCD3/main.cpp:-1: In function 'int main(int, char**)':
/Qt Practice/LCD3/LCD3/main.cpp:10: error: expected type-specifier before 'Test'

Means the type "Test" is not know.
Indeed you don't have such a class, your class is called "ClassA"

/Qt Practice/LCD3/LCD3/main.cpp:10: error: cannot convert 'int*' to 'ClassA*' in initialization
/Qt Practice/LCD3/LCD3/main.cpp:10: error: expected ',' or ';' before 'Test'

These are just follow-up errors because of the one before, they will go away once you fixed the other one.

Cheers,
_