?
Solved

class instance not visible...

Posted on 2004-08-19
4
Medium Priority
?
215 Views
Last Modified: 2012-05-05
Hi all,

I've got:

void myFunction(){
   try{
      CSpec CS("param1");
   }catch(exception e){
      //Do recovery things...
   }

   if(something){
      CS.method();
   }
}

...problem is, is that CS.method(); isn't recognised since CS is in a different scope (???)....I can't do this:

void myFunction(){
   try{
      CSpec CS("param1");
      if(something){
         CS.method();
      }
   }catch(exception e){
      //Do recovery things...
   }
}

because I've got plenty of those if(something)'s...so I don't really want hundreds of nested if's like that...
0
Comment
Question by:Unimatrix_001
4 Comments
 
LVL 3

Expert Comment

by:Indrawati
ID: 11848462
I think it's better if you code it this way:

try
{
     MyFunction();
}
catch(exception &e)
{
}

You don't need to explicitly specify try/catch inside MyFunction() anymore.
0
 
LVL 30

Accepted Solution

by:
Axter earned 390 total points
ID: 11848554
You can use a pointer instead.
void myFunction(){
 CSpec *CS_ptr = NULL;
  try{
     CS_ptr  = new CSpec("param1");
  }catch(exception e){
     //Do recovery things...
  }
   CSpec &CS = *CS_ptr;
  if(something){
     CS.method();
  }
}

By using a pointer, you can delay creating the object until it's in the try{} scope.
By using a reference after the try/catch, you can reference the pointer, and then use the reference variable, which has the same syntax as a static variable.
0
 
LVL 17

Assisted Solution

by:rstaveley
rstaveley earned 360 total points
ID: 11850570
If the exception is thrown in the ctor, Axter's approach wouldn't work, because the instance of CSpec will not have been constructed and the CS_ptr will continue to point to NULL.

Careful with this:

   CSpec &CS = *CS_ptr;

You need to test for a NULL pointer before dereferencing CS_ptr.
0
 
LVL 3

Author Comment

by:Unimatrix_001
ID: 11853361
Thanks :)
0

Featured Post

How to Use the Help Bell

Need to boost the visibility of your question for solutions? Use the Experts Exchange Help Bell to confirm priority levels and contact subject-matter experts for question attention.  Check out this how-to article for more information.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

What is C++ STL?: STL stands for Standard Template Library and is a part of standard C++ libraries. It contains many useful data structures (containers) and algorithms, which can spare you a lot of the time. Today we will look at the STL Vector. …
Introduction This article is a continuation of the C/C++ Visual Studio Express debugger series. Part 1 provided a quick start guide in using the debugger. Part 2 focused on additional topics in breakpoints. As your assignments become a little more …
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.
Suggested Courses

839 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question