initialization of ‘element’ is skipped by ‘case’ label [duplicate]

Try wrap case with {}, and put all your statement inside {}.

case 1:
{
   cout << endl << endl << "Current S = ";
   this->printSet();    
   // and other mess
}
break;

You should put all these statement in functions, keep case statement clear. For example, write this style:

case 1:
   initializeElement();
   break;
case 2:
   doSomethingElse();
   break;

See link