i downloaded a book about qt programming but its outdated because its version is something like qt4. while i got the latest Qt5.0.2 creator and compiler which i downloaded from qt-project.org/downloads. I've read from chapter 1 and everything seems to work fine but when i reached chapter 2, which includes header, thebody and the main, i received a lot of errors so here is my code...im running windows

in the creator i clicked--File->New Project->Other Project->Empty Qt Project->then i named it finddialog->next2x->Finished

then in the project named finddialog i right clicked it->Add New->C++ Source File->i named it main.cpp->then finished.

then in the project named finddialog again i right clicked it->Add New->C++ Class->class name: finddialog, base class: i chose QWidget->then Finished.

so here is the code in the header file...
Qt Code: 
  1. #ifndef FINDDIALOG_H
  2. 2 #define FINDDIALOG_H
  3.  
  4. 3 #include <QDialog>
  5.  
  6. 4 class QCheckBox;
  7. 5 class QLabel;
  8. 6 class QLineEdit;
  9. 7 class QPushButton;
  10. 8 class FindDialog : public QDialog
  11.  9 {
  12. 10     Q_OBJECT
  13.  
  14. 11 public:
  15. 12     FindDialog(QWidget *parent = 0);
  16. 13 signals:
  17. 14     void findNext(const QString &str, Qt::CaseSensitivity cs);
  18. 15     void findPrevious(const QString &str, Qt::CaseSensitivity cs);
  19. 16 private slots:
  20. 17     void findClicked();
  21. 18     void enableFindButton(const QString &text);
  22.  
  23. 19 private:
  24. 20     QLabel *label;
  25. 21     QLineEdit *lineEdit;
  26. 22     QCheckBox *caseCheckBox;
  27. 23     QCheckBox *backwardCheckBox;
  28. 24     QPushButton *findButton;
  29. 25     QPushButton *closeButton;
  30. 26 };
  31.  
  32. 27 #endif
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then in the finddialog.cpp here is the code
Qt Code: 
  1. 1 #include <QtGui>
  2.  
  3. 2 #include "finddialog.h"
  4. 3 FindDialog::FindDialog(QWidget *parent)
  5.  4     : QDialog(parent)
  6.  5 {
  7.  6     label = new QLabel(tr("Find &what:"));
  8.  7     lineEdit = new QLineEdit;
  9.  8     label->setBuddy(lineEdit);
  10.  
  11.  9     caseCheckBox = new QCheckBox(tr("Match &case"));
  12. 10     backwardCheckBox = new QCheckBox(tr("Search &backward"));
  13.  
  14. 11     findButton = new QPushButton(tr("&Find"));
  15. 12     findButton->setDefault(true);
  16. 13     findButton->setEnabled(false);
  17.  
  18. 14     closeButton = new QPushButton(tr("Close"));
  19.  
  20. 15   connect(lineEdit, SIGNAL(textChanged(const QString &)),
  21. 16           this, SLOT(enableFindButton(const QString &)));
  22. 17   connect(findButton, SIGNAL(clicked()),
  23. 18           this, SLOT(findClicked()));
  24. 19   connect(closeButton, SIGNAL(clicked()),
  25. 20           this, SLOT(close()));
  26. 21    QHBoxLayout *topLeftLayout = new QHBoxLayout;
  27. 22    topLeftLayout->addWidget(label);
  28. 23    topLeftLayout->addWidget(lineEdit);
  29.  
  30. 24    QVBoxLayout *leftLayout = new QVBoxLayout;
  31. 25    leftLayout->addLayout(topLeftLayout);
  32. 26    leftLayout->addWidget(caseCheckBox);
  33. 27    leftLayout->addWidget(backwardCheckBox);
  34.  
  35. 28    QVBoxLayout *rightLayout = new QVBoxLayout;
  36. 29    rightLayout->addWidget(findButton);
  37. 30    rightLayout->addWidget(closeButton);
  38. 31    rightLayout->addStretch();
  39.  
  40. 32    QHBoxLayout *mainLayout = new QHBoxLayout;
  41. 33    mainLayout->addLayout(leftLayout);
  42. 34    mainLayout->addLayout(rightLayout);
  43. 35    setLayout(mainLayout);
  44. 36    setWindowTitle(tr("Find"));
  45. 37    setFixedHeight(sizeHint().height());
  46. 38 }
  47. 39 void FindDialog::findClicked()
  48. 40 {
  49. 41     QString text = lineEdit->text();
  50. 42     Qt::CaseSensitivity cs =
  51. 43             caseCheckBox->isChecked() ? Qt::CaseSensitive
  52. 44                                       : Qt::CaseInsensitive;
  53. 45     if (backwardCheckBox->isChecked()) {
  54. 46         emit findPrevious(text, cs);
  55. 47     } else {
  56. 48         emit findNext(text, cs);
  57. 49     }
  58. 50 }
  59.  
  60. 51 void FindDialog::enableFindButton(const QString &text)
  61. 52 {
  62. 53     findButton->setEnabled(!text.isEmpty());
  63. 54 }
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and the last one in is the main.cpp here it is....
Qt Code: 
  1. 1 #include <QWidgets/QApplication>
  2.  
  3. 2 #include "finddialog.h"
  4.  
  5. 3 int main(int argc, char *argv[])
  6. 4 {
  7. 5     QApplication app(argc, argv);
  8. 6     FindDialog *dialog = new FindDialog;
  9. 7     dialog->show();
  10. 8     return app.exec();
  11. 9 }
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When run and compile this i got 46 errors.
In the .pro file i did type this QT += widgets

Did i miss something more important? The codes the i entered above will surely works on qt4 but im currently running the latest Qt5.0.2 packaged which i thought will not give me problems...