Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

class instance not visible...

Posted on 2004-08-19
4
197 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 130 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 120 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

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Suggested Solutions

This article shows you how to optimize memory allocations in C++ using placement new. Applicable especially to usecases dealing with creation of large number of objects. A brief on problem: Lets take example problem for simplicity: - I have a G…
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…
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.

856 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