What's wrong?

Qt Code: 
  1. void XmlGenerator::sourceWrite(QTextEdit* editor){
  2. 	if(!f->open(QIODevice::ReadWrite|QIODevice::Truncate))
  3. 		std::cout<<"f problem"<<std::endl;
  4.  
  5. 	if(!file->open(QIODevice::ReadWrite))
  6. 		std::cout<<"f problem"<<std::endl;
  7.  
  8. 	QTextStream in(file);
  9. 	QTextStream out(f);
  10. 	QString line;
  11. 	 while(!(line=in.readLine()).isNull()){
  12. 	if(!line.isEmpty()){
  13.     if(line.at(0).toLatin1() != '<'){
  14.     out<<line<<"\n";
  15.     editor->setPlainText(line)<<"\n";
  16.    }
  17.   }
  18.  }//while
  19.  out<<"END";
  20.  editor->setPlainText("END");
  21.  f->close();
  22.  file->close();
  23. }
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If I put a comment on line number 15, it compiles without any error, so i think that line is the problem........