Something

#include "checkable.h"
#include <QLabel>
#include <QLineEdit>
#include <QPushButton>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QGridLayout>
#include <QIntValidator>
#include <QRegExpValidator>

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("Hex"));
    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);

    // Limit input to valid values
    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()));
    connect(decEdit, SIGNAL(textChanged(const QString&)),
            this, SLOT(decChanged(const QString&)));
    connect(hexEdit, SIGNAL(textChanged(const QString&)),
            this, SLOT(hexChanged(const QString&)));
    connect(binEdit, SIGNAL(textChanged(const QString&)),
            this, SLOT(binChanged(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, 16);
    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, 2);
    if (ok) {
        decEdit->setText(QString::number(num));
        hexEdit->setText(QString::number(num, 16));
    } else {
        decEdit->setText("");
        hexEdit->setText("");
    }
}