I am a newbie for c++ as well as qt. I am trying some example, which i pasted it for
easy understanding. I am trying to compile it through qmake and make command line tool. It compiles successfully but when i try to execute it no form is displayed.
please look into the code help me where i am doing mistake....

Qt Code: 
  1. //finddialog.h file
  2.  
  3. #ifndef FINDDIALOG_H
  4. #define FINDDIALOG_H
  5.  
  6. #include<QDialog>
  7.  
  8. class QLineEdit;
  9. class QCheckBox;
  10. class QLabel;
  12.  
  13. class FindDialog:public QDialog
  14. {
  15.   Q_OBJECT
  16. public:
  17.   FindDialog(QWidget *parent=0);
  18.  
  19. signals:
  20.   void findNext(const QString &str,Qt::CaseSensitivity cs);
  21.   void findPrevious(const QString &str,Qt::CaseSensitivity cs);
  22.  
  23. public slots:
  24.   void findClicked();
  25.   void enableFindButton(const QString &text);
  26.  
  27. private:
  28.   QLabel *label;
  29.   QLineEdit *lineEdit;
  30.   QCheckBox *caseCheckBox;
  31.   QCheckBox *backwardCheckBox;
  32.   QPushButton *findButton;
  33.   QPushButton *closeButton;
  34. };
  35. #endif
  36. //************************************************
  37. //finddialog.cpp
  38. #include<QtGui>
  39. #include "finddialog.h"
  40.  
  41. FindDialog::FindDialog(QWidget *parent):QDialog(parent)
  42. {
  43.   label=new QLabel("Find &what: ");
  44.   lineEdit=new QLineEdit;
  45.   label->setBuddy(lineEdit);
  46.  
  47.   caseCheckBox=new QCheckBox("Match &case");
  48.   backwardCheckBox=new QCheckBox("Search &backward");
  49.  
  50.   findButton=new QPushButton("&Find");
  51.   findButton->setDefault(true);
  52.   findButton->setEnabled(false);
  53.  
  54.   closeButton=new QPushButton("Close");
  55.  
  56.   connect(lineEdit,SIGNAL(textChanged(const QString &)),
  57. 	  this,SLOT(enableFindButton(const QString &)));
  58.   connect(findButton,SIGNAL(clicked()),
  59. 	  this,SLOT(findClicked()));
  60.   connect(closeButton,SIGNAL(clicked()),
  61. 	  this,SLOT(close()));
  62.  
  63.   QHBoxLayout *topleftLayout=new QHBoxLayout;
  64.   topleftLayout->addWidget(label);
  65.   topleftLayout->addWidget(lineEdit);
  66.  
  67.   QVBoxLayout *leftLayout=new QVBoxLayout;
  68.   leftLayout->addLayout(topleftLayout);
  69.   leftLayout->addWidget(caseCheckBox);
  70.   leftLayout->addWidget(backwardCheckBox);
  71.  
  72.   QVBoxLayout *rightLayout=new QVBoxLayout;
  73.   rightLayout->addWidget(findButton);
  74.   rightLayout->addWidget(closeButton);
  75.   rightLayout->addStretch();
  76.  
  77.   QHBoxLayout *mainLayout=new QHBoxLayout;
  78.   rightLayout->addLayout(leftLayout);
  79.   rightLayout->addLayout(rightLayout);
  80.   setLayout(mainLayout);
  81.  
  82.   setWindowTitle("Find");
  83.   setFixedHeight(sizeHint().height());
  84. }
  85.  
  86. void FindDialog::findClicked()
  87. {
  88.   QString text=lineEdit->text();
  89.   Qt::CaseSensitivity cs=caseCheckBox->isChecked()?
  90.     Qt::CaseSensitive:Qt::CaseInsensitive;
  91.  
  92.   if(backwardCheckBox->isChecked())
  93.   {
  94.     emit findPrevious(text,cs);
  95.   }
  96.   else
  97.   {
  98.     emit findNext(text,cs);
  99.   }
  100. }
  101.  
  102. void FindDialog::enableFindButton(const QString &text)
  103. {
  104.   findButton->setEnabled(!text.isEmpty());
  105. }
  106. //*****************************************************
  107. //main.cpp file
  108.  
  109. #include<QApplication>
  110. #include "finddialog.h"
  111.  
  112. int main(int argc,char *argv[])
  113. {
  114.   QApplication app(argc,argv);
  115.   FindDialog *dialog=new FindDialog;
  116.   dialog->show();
  117.   return app.exec();
  118. }
  119. //****************************
  120.  
  121. //subdialog.pro file
  122.  
  123. ######################################################################
  124. # Automatically generated by qmake (2.01a) Sat Oct 16 23:27:20 2010
  125. ######################################################################
  126.  
  127. TEMPLATE = app
  128. TARGET = 
  129. DEPENDPATH += .
  130. INCLUDEPATH += .
  131.  
  132. # Input
  133. HEADERS += finddialog.h
  134. SOURCES += finddialog.cpp main.cpp
  135. //*********************
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