title: symbol(s) not found for architecture x86_64 mac os 10.13.3
body: <p>I know this question was already asked like a thousand times but i tried every solution and nothing helped.</p>
  
  <p>I made a little program in Qt and after a while i got this error message:</p>
  
  <pre><code>symbol(s) not found for architecture x86_64
  linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <p>I redid the <code>qmake</code> command and the rebuild project, nothing worked.
  I'm new in Qt.
  I am using Qt version 5.10.0 on mac os 10.13.3</p>
  
  <p>Here are my files:</p>
  
  <p>gui.h</p>
  
  <pre><code>#ifndef GUI_H
  #define GUI_H
  
  #include &lt;QWidget&gt;
  #include &lt;QPainter&gt;
  
  #include &lt;QHBoxLayout&gt;
  #include &lt;QVBoxLayout&gt;
  
  #include &lt;QPushButton&gt;
  #include &lt;QLineEdit&gt;
  
  class gui : public QWidget
  {
      Q_OBJECT
  
  public:
      gui(QWidget *parent = 0);
      ~gui();
  
  private:
      QHBoxLayout *hbox1;
      QHBoxLayout *hbox2;
      QVBoxLayout *vbox;
  
      QPushButton *search;
      QPushButton *replace;
  
      QLineEdit *searchText;
      QLineEdit *replaceText;
      QLineEdit *textField;
  
  public slots:
  
      void find();
      void replaceFuckingText();
  };
  
  #endif // GUI_H
  </code></pre>
  
  <p>gui.cpp</p>
  
  <pre><code>#include "gui.h"
  
  gui::gui(QWidget *parent)
      : QWidget(parent)
  {
  
      hbox1 = new QHBoxLayout();
      hbox2 = new QHBoxLayout();
      vbox = new QVBoxLayout();
  
      search = new QPushButton("Search");
      replace = new QPushButton("Replace");
  
      searchText = new QLineEdit();
      replaceText = new QLineEdit();
      textField = new QLineEdit();
  
      hbox1-&gt;addWidget(searchText);
      hbox1-&gt;addWidget(replaceText);
  
      vbox-&gt;addLayout(hbox1);
  
      hbox2-&gt;addWidget(search);
      hbox2-&gt;addWidget(replace);
  
      vbox-&gt;addLayout(hbox2);
  
      vbox-&gt;addWidget(textField);
  
      setLayout(vbox);
      show();
  
      connect(replace,SIGNAL(clicked()), this, SLOT(replaceFuckingText()));
  
  }
  
  gui::~gui()
  {
  
  }
  
  void gui::replaceFuckingText() {
      QString searchTextValue = searchText-&gt;text();
      QString replaceTextValue = replaceText-&gt;text();
      QString textToReplace = textField-&gt;text();
  
      textToReplace.replace(searchTextValue,replaceTextValue);
  
      textField-&gt;setText(textToReplace);
  }
  </code></pre>
  
  <p>main.cpp:</p>
  
  <pre><code>#include "gui.h"
  #include &lt;QApplication&gt;
  
  int main(int argc, char *argv[])
  {
      QApplication a(argc, argv);
      gui w;
      w.show();
  
      return a.exec();
  }
  </code></pre>
  
  <p>I hope you can help me. I'm working on this error for over a week now.
  If you need more informations feel free to ask and I'll post them. </p>