Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

try... catch problem

Posted on 2011-02-17
8
Medium Priority
?
433 Views
Last Modified: 2012-05-11
Hello Experts!

Please have a look at the code below.

I expect to catch exception, instead I get exception risen by vector code and it crashes my application.

What do I do wrong here?

Thank you

panJames

#include <vector>
#include <iostream>
#include <exception>

using namespace std;

void main()
{
	int a;
	std::vector<int> abc;

	abc.push_back(1);
	abc.push_back(2);

	try
	{
		a = abc[2];
	}
	catch (exception& e)
	{
		cout << e.what();

	}

}

Open in new window

0
Comment
Question by:panJames
[X]
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
  • 3
  • 2
  • 2
  • +1
8 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 34917482
you need to put the try larger:
#include <vector>
#include <iostream>
#include <exception>

using namespace std;

void main()
{
        try
        {
        int a;
        std::vector<int> abc;

        abc.push_back(1);
        abc.push_back(2);

                a = abc[2];
        }
        catch (exception& e)
        {
                cout << e.what();

        }

}

Open in new window

0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 34917533
To further angelIII's comment, you only reserved the space--you didn't actually initialize it, so you are trying to call a method on a null object, hence the exception.
0
 
LVL 53

Accepted Solution

by:
Infinity08 earned 2000 total points
ID: 34917618
The operator[] for std::vector doesn't throw an exception, so you can't expect to catch it. If you want to get an exception, use the at method :
try
	{
		a = abc.at(2);
	}
	catch (exception& e)
	{
		cout << e.what();
	}

Open in new window

0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Author Comment

by:panJames
ID: 34917653
@angelIII:

1. Why do I need larger try{} selection? Thought that I need to make my try{} where I expect it to crash...
2. It does not help anyway. Program never comes to line:

 cout << e.what();

0
 

Author Comment

by:panJames
ID: 34917661
@kaufmed: I know it.

panJames
0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 34917724
>>  @kaufmed: I know it.


Uhhh...   then you have your answer  = )

Calling a method on an uninstantiated object raises an exception.
0
 

Author Comment

by:panJames
ID: 34917757
@Infinity08:

I am confused now.

My understanding of try{} was that if anything wrong happens inside try{} then exception is thrown and all I need to do is to catch it (like in Delphi).

So C++ program does not have such functionality?

How can I catch something simple like:


int a = 12;
int b = 0;
int c;


try
{
 c = a / b;
}


panJames
0
 
LVL 53

Expert Comment

by:Infinity08
ID: 34917781
>> My understanding of try{} was that if anything wrong happens inside try{} then exception is thrown and all I need to do is to catch it (like in Delphi).

No, not anything. Anything that throws a C++ exception will be caught if you have an appropriate catch handler. But divisions by 0 or segmentation faults eg. won't.


>> So C++ program does not have such functionality?

Some compilers might add it as an extension, but it's not generally available no.
0

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say 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

IntroductionThis article is the second in a three part article series on the Visual Studio 2008 Debugger.  It provides tips in setting and using breakpoints. If not familiar with this debugger, you can find a basic introduction in the EE article loc…
This is a short and sweet, but (hopefully) to the point article. There seems to be some fundamental misunderstanding about the function prototype for the "main" function in C and C++, more specifically what type this function should return. I see so…
Video by: Grant
The goal of this video is to provide viewers with basic examples to understand and use while-loops in the C programming language.
The viewer will learn how to pass data into a function in C++. This is one step further in using functions. Instead of only printing text onto the console, the function will be able to perform calculations with argumentents given by the user.

721 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