• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 438
  • Last Modified:

try... catch problem

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
panJames
Asked:
panJames
  • 3
  • 2
  • 2
  • +1
1 Solution
 
Guy Hengel [angelIII / a3]Billing EngineerCommented:
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
 
käµfm³d 👽Commented:
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
 
Infinity08Commented:
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
Cloud Class® Course: Python 3 Fundamentals

This course will teach participants about installing and configuring Python, syntax, importing, statements, types, strings, booleans, files, lists, tuples, comprehensions, functions, and classes.

 
panJamesAuthor Commented:
@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
 
panJamesAuthor Commented:
@kaufmed: I know it.

panJames
0
 
käµfm³d 👽Commented:
>>  @kaufmed: I know it.


Uhhh...   then you have your answer  = )

Calling a method on an uninstantiated object raises an exception.
0
 
panJamesAuthor Commented:
@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
 
Infinity08Commented:
>> 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
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

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.

  • 3
  • 2
  • 2
  • +1
Tackle projects and never again get stuck behind a technical roadblock.
Join Now