Re: Problem in C++ program

From:
Robert Bauck Hamar <roberth+news@ifi.uio.no>
Newsgroups:
comp.lang.c++
Date:
Sat, 07 Jul 2007 00:29:21 +0200
Message-ID:
<f6mfo1$ftb$1@readme.uio.no>
 bazymew@gmail.com wrote:

   I'm new to C++(I've only started learning about a month ago), so
please don't call me stupid for asking a dumb question.


Good luck with learning.

   You see I was experimenting with Exception operators, trying to
make a program not lock up or quit right away when you enter a non
integer value.


It's always a good idea to validate input. However C++ doesn't work just
like you expect. An int variable is still an int variable even though your
input failed, and that's what C++ would look for.

Now, even if you enter an integer value, it says to
enter an integer value. I hadf it set up so that the second time you
enter a non integer value, it quits. Now, the second time you enter
any value, it quits. Here's a section of the source code:

cin >> integer;


What's integer? That is: How is it defined?
int integer?
std::string integer?

  try
  {
    throw integer;
  }
  catch (int ncn)


If integer is defined as:
int integer;
this would work, and set ncn to the value of integer. This happens even if
the input failed.

  {
    name = new char[ncn];


The name name suggests that name should be a string. You should look up the
std::string class. Doesn't your book/teacher explain it?

  }
  catch (...)


If integer is defined as anything but int, this would happen.

  {
    cout << "Please enter an integer value.\n" << "If you enter a non
integer value a second time, the program will end.";
    cin >> integer;
    try
    {
      throw integer;
    }
    catch (int ncn)


This could never happen.

    {
      name = new char[ncn];
    }
    catch (...)
    {
      return (0);
    }
  }


--
rbh

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