What is this error in the code?

Question

while working in try-catch in came across this error. But I cant trace out the reason for this error though I surfed the net and SO.

My code is...

int main()
{
Queue q;
int choice,data;

 while(1)
 {
  choice  = getUserOption();
  switch(choice)
  {
   case 1:
     cout<<"\nEnter an element:";
     cin>>data;
     q.enqueue(data);
     break;
   case 2:
     int element;
     element = q.dequeue();
     cout<<"Element Dequeued:\n"<<element;
     break;
   case 3:
     q.view();
     break;
   case 4:
     exit(EXIT_SUCCESS);
  }
  catch(UnderFlowException e)
  {
   cout<<e.display();
  }
  catch(OverFlowException e)
  {
   cout<<e.display();
  }

 }// end of while(1)

       return 0;
}

For me everything in the above code seems to be correct. But g++ complier is throwing...

muthu@muthu-G31M-ES2L:~/LangFiles/cppfiles/2ndYearLabException$ g++ ExceptionHandlingEdited.cpp
ExceptionHandlingEdited.cpp: In member function ‘void Queue::enqueue(int)’:
ExceptionHandlingEdited.cpp:89:97: warning: deprecated conversion from string constant to ‘char*’
ExceptionHandlingEdited.cpp: In member function ‘int Queue::dequeue()’:
ExceptionHandlingEdited.cpp:113:95: warning: deprecated conversion from string constant to ‘char*’
ExceptionHandlingEdited.cpp: In member function ‘void Queue::view()’:
ExceptionHandlingEdited.cpp:140:66: warning: deprecated conversion from string constant to ‘char*’
ExceptionHandlingEdited.cpp: In function ‘int main()’:
ExceptionHandlingEdited.cpp:185:3: error: expected primary-expression before ‘catch’
ExceptionHandlingEdited.cpp:185:3: error: expected ‘;’ before ‘catch’
ExceptionHandlingEdited.cpp:189:3: error: expected primary-expression before ‘catch’
ExceptionHandlingEdited.cpp:189:3: error: expected ‘;’ before ‘catch’

Apart from the answers, `deprecated conversion from string constant to ‘char*’` is also an important warning. Make sure that you use `const char*` for string literals. — iammilind, Sep 27 '11 at 03:10

score 5 · Accepted Answer · answered Sep 27 '11 at 01:41

You can't have a catch without a try. Put the line:

try {

before your while statement.

If you want to get rid of the warnings about the string constants, you'll probably have to change the types to const char * or explicitly cast/copy them. Or you can use the -Wno-write-strings option to gcc.

score 4 · Answer 2 · answered Sep 27 '11 at 01:47

4

You need to surround your code in try {...} construct, otherwise catch will not know what code it should catch.

Wrap your while loop into try:

try {
 while(1)
   {
    .....
   }// end of while(1)
} catch(UnderFlowException e) ...

Reference.

answered Sep 27 '11 at 01:47

evgeny

2,564
17
27

score 0 · Answer 3 · answered Sep 27 '11 at 10:35

Try this:

int main()
{
Queue q;
int choice,data;

 while(1)
 {
  choice  = getUserOption();
  try 
  {
    switch(choice)
    {
     case 1:
       cout<<"\nEnter an element:";
       cin>>data;
       q.enqueue(data);
       break;
     case 2:
       int element;
       element = q.dequeue();
       cout<<"Element Dequeued:\n"<<element;
       break;
     case 3:
       q.view();
       break;
     case 4:
       exit(EXIT_SUCCESS);
    }
  }
  catch(UnderFlowException e)
  {
   cout<<e.display();
  }
  catch(OverFlowException e)
  {
   cout<<e.display();
  }

 }// end of while(1)

       return 0;
}

What is this error in the code?

3 Answers3