need help in qt code

hi

i am following "The Book Of Qt 4 The art of Building Qt Applications" and trying the following example which converts byte to decimal, hexadecimal and binary but when i run, it produces error

here is the code
byteconverterdialog.h file

Code:

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#ifndef BYTECONVERTERDIALOG_H
#define BYTECONVERTERDIALOG_H
 
#include <QDialog>
 
class byteConverterDialog : public QDialog
{
    Q_OBJECT
 
public:
    byteConverterDialog();
};
 
#endif // BYTECONVERTERDIALOG_H

---

byteconverter.h

Code:

---

#ifndef BYTECONVERTER_H
#define BYTECONVERTER_H
 
#include <QObject>
 
class ByteConverter : public QObject
{
    Q_OBJECT
 
public:
    ByteConverter(QObject* = 0);
 
public slots:
    void setDec(const QString &);
    void setHex(const QString &);
    void setBin(const QString &);
 
signals:
    void decChanged(const QString&);
    void hexChanged(const QString&);
    void binChanged(const QString&);
};
 
#endif // BYTECONVERTER_H

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byteconverterdialog.cpp

Code:

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#include "byteconverterdialog.h"
#include "byteconverter.h"
#include <QLabel>
#include <QLineEdit>
#include <QPushButton>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QGridLayout>
#include <QIntValidator>
 
byteConverterDialog::byteConverterDialog()
{
    //generate the necessary layouts
    QVBoxLayout *mainLayout = new QVBoxLayout(this);
    QGridLayout *editLayout = new QGridLayout;
    QHBoxLayout *buttonLayout = new QHBoxLayout;
 
    mainLayout->addLayout(editLayout);
    mainLayout->addStretch();
    mainLayout->addLayout(buttonLayout);
 
    //generate the labels and line-edits and add them to the object pointed at by editLayout
    QLabel *decLabel = new QLabel(tr("Decimal"));
    QLabel *hexLabel = new QLabel(tr("hexadecimal"));
    QLabel *binLabel = new QLabel(tr("Binary"));
 
    decEdit = new QLineEdit;
    hexEdit = new QLineEdit;
    binEdit = new QLineEdit;
 
    editLayout->addWidget(decLabel, 0, 0);
    editLayout->addWidget(decEdit, 0, 1);
    editLayout->addWidget(hexLabel, 1, 0);
    editLayout->addWidget(hexEdit, 1, 1);
    editLayout->addWidget(binLabel, 2, 0);
    editLayout->addWidget(binEdit, 2, 1);
 
    //create the quit button and add it to the object pointed at by buttonLayout.
    QPushButton *exitButton = new QPushButton(tr("Quit"));
 
    buttonLayout->addStretch();
    buttonLayout->addWidget(exitButton);
    exitButton->setDefault(true);
 
    QIntValidator* decValidator =
    new QIntValidator(0, 255, decEdit);
    decEdit->setValidator(decValidator);
    QRegExpValidator* hexValidator =
    new QRegExpValidator(QRegExp("[0-9A-Fa-f]{1,2}"), hexEdit);
    hexEdit->setValidator(hexValidator);
    QRegExpValidator* binValidator =
    new QRegExpValidator(QRegExp("[01]{1,8}"), binEdit);
    binEdit->setValidator(binValidator);
 
    setWindowTitle(tr("Byte Converter"));
 
    connect(exitButton, SIGNAL(clicked()), this, SLOT(accept()));
 
    ByteConverter* bc = new ByteConverter(this);
 
    connect(decEdit, SIGNAL(textChanged(const QString &)), bc, SLOT(setDec(const QString &)));
    connect(hexEdit, SIGNAL(textChanged(const QString &)), bc, SLOT(setHex(const QString &)));
    connect(binEdit, SIGNAL(textChanged(const QString &)), bc, SLOT(setBin(const QString &)));
 
    connect(bc, SIGNAL(decChanged(const QString&)), decEdit, SLOT(setText(const QString&)));
    connect(bc, SIGNAL(hexChanged(const QString&)), hexEdit, SLOT(setText(const QString&)));
    connect(bc, SIGNAL(binChanged(const QString&)), binEdit, SLOT(setText(const QString&)));
}
 
void byteConverterDialog::decChanged(const QString& newValue)
{
    bool ok;
    int num = newValue.toInt(&ok);
    if(ok) {
        hexEdit->setText(QString::number(num, 16));
        binEdit->setText(QString::number(num, 2));
    }
    else {
        hexEdit->setText("");
        binEdit->setText("");
    }
}
 
void byteConverterDialog::hexChanged(const QString& newValue)
{
    bool ok;
    int num = newValue.toInt(&ok);
    if(ok) {
        decEdit->setText(QString::number(num));
        binEdit->setText(QString::number(num, 2));
    }
    else {
        decEdit->setText("");
        binEdit->setText("");
    }
}
 
void byteConverterDialog::binChanged(const QString& newValue)
{
    bool ok;
    int num = newValue.toInt(&ok);
    if(ok) {
        decEdit->setText(QString::number(num));
        hexEdit->setText(QString::number(num, 16));
    }
    else {
        hexEdit->setText("");
        decEdit->setText("");
    }
}

---

byteconverter.cpp

Code:

---

#include "byteconverter.h"
 
ByteConverter::ByteConverter(QObject* parent) : QObject(parent)
{
}
 
void ByteConverter::setDec(const QString& newValue)
{
    bool ok;
    int num = newValue.toInt(&ok);
    if(ok) {
        emit hexChanged(QString::number(num, 16));
        emit binChanged(QString::number(num, 2));
    }
    else {
        emit hexChanged("");
        emit binChanged("");
    }
}
 
void ByteConverter::setHex(const QString& newValue)
{
    bool ok;
    int num = newValue.toInt(&ok, 16);
    if(ok) {
        emit decChanged(QString::number(num));
        emit binChanged(QString::number(num, 2));
    }
    else {
        emit decChanged("");
        emit binChanged("");
    }
}
 
void ByteConverter::setBin(const QString& newValue)
{
    bool ok;
    int num = newValue.toInt(&ok, 2);
    if(ok) {
        emit decChanged(QString::number(num));
        emit hexChanged(QString::number(num, 16));
    }
    else {
        emit decChanged("");
        emit hexChanged("");
    }
}

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main.cpp

Code:

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#include <QtGui/QApplication>
#include "byteconverterdialog.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    byteConverterDialog bc;
    bc.setAttribute(Qt::WA_QuitOnClose);
    bc.show();
 
    return a.exec();
}

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when i run this code, it displays these errors

Code:

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decEdit was not declared in this scope  byteconverterdialog.cpp 27
hexEdit was not declared in this scope  byteconverterdialog.cpp 28
binEdit was not declared in this scope  byteconverterdialog.cpp 29
 
void byteConverterDialog::decChanged(const QString&) member function declared in class byteConverterDialog   byteconverterdialog.cpp 70
void byteConverterDialog::hexChanged(const QString&) member function declared in class byteConverterDialog   byteconverterdialog.cpp 84
void byteConverterDialog::binChanged(const QString&) member function declared in class byteConverterDialog   byteconverterdialog.cpp 98

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As the error says... you have not declared decEdit,hexEdit and binEdit...
Something like QLineEdit * decEdit = new QLineEdit;
or m_decEdit = new QLineEdit; // Where m_decEdit is member variable.

in which class should i declare these?

this is what i got in Compile Output tab

Code:

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Running build steps for project byteConverter...
Configuration unchanged, skipping qmake step.
Starting: "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" -w 
mingw32-make: Entering directory `C:/Users/Administrator/Documents/byteConverter-build-desktop' 
C:/Qt/2010.04/mingw/bin/mingw32-make -f Makefile.Debug 
mingw32-make[1]: Entering directory `C:/Users/Administrator/Documents/byteConverter-build-desktop' 
g++ -c -g -frtti -fexceptions -mthreads -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -DQT_DLL -DQT_GUI_LIB -DQT_CORE_LIB -DQT_THREAD_SUPPORT -DQT_NEEDS_QMAIN -I"..\..\..\..\Qt\2010.04\qt\include\QtCore" -I"..\..\..\..\Qt\2010.04\qt\include\QtGui" -I"..\..\..\..\Qt\2010.04\qt\include" -I"..\..\..\..\Qt\2010.04\qt\include\ActiveQt" -I"debug" -I"." -I"..\byteConverter" -I"." -I"..\..\..\..\Qt\2010.04\qt\mkspecs\win32-g++" -o debug\byteconverterdialog.o ..\byteConverter\byteconverterdialog.cpp 
mingw32-make[1]: Leaving directory `C:/Users/Administrator/Documents/byteConverter-build-desktop' 
mingw32-make: Leaving directory `C:/Users/Administrator/Documents/byteConverter-build-desktop' 
..\byteConverter\byteconverterdialog.cpp: In constructor 'byteConverterDialog::byteConverterDialog()': 
..\byteConverter\byteconverterdialog.cpp:27: error: 'm_decEdit' was not declared in this scope 
..\byteConverter\byteconverterdialog.cpp:28: error: 'hexEdit' was not declared in this scope 
..\byteConverter\byteconverterdialog.cpp:29: error: 'binEdit' was not declared in this scope 
..\byteConverter\byteconverterdialog.cpp:32: error: 'decEdit' was not declared in this scope 
..\byteConverter\byteconverterdialog.cpp: At global scope: 
..\byteConverter\byteconverterdialog.cpp:70: error: no 'void byteConverterDialog::decChanged(const QString&)' member function declared in class 'byteConverterDialog' 
..\byteConverter\byteconverterdialog.cpp:84: error: no 'void byteConverterDialog::hexChanged(const QString&)' member function declared in class 'byteConverterDialog' 
..\byteConverter\byteconverterdialog.cpp:98: error: no 'void byteConverterDialog::binChanged(const QString&)' member function declared in class 'byteConverterDialog' 
mingw32-make[1]: *** [debug/byteconverterdialog.o] Error 1 
mingw32-make: *** [debug] Error 2 
The process "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" exited with code %2.
Error while building project byteConverter (target: Desktop)
When executing build step 'Make'

---

A variable needs to be of some type..
you cannot simply write
xyz = something; You need to define what type of is xyz, is it int, QString, QWidget etc...

To answer your question of where to add it:

Code:

---

#ifndef BYTECONVERTERDIALOG_H
#define BYTECONVERTERDIALOG_H
 
#include <QDialog>
 
class byteConverterDialog : public QDialog
{
    Q_OBJECT
 
public:
    byteConverterDialog();
 
private:
    // <----------Here. 
};
 
#endif // BYTECONVERTERDIALOG_H

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