constructor problem

As a part of an exercise I need to built Drawing class that contains an array
of pointers to objects from other classes (different types of shapes)
I have a few problems with the constructor.
at first I tried:

Code:

---

typedef shape* pshape;
...

Drawing(int n=10) :size_(n)
  {
        drawing_ = new pshape[n];
        for (int i=0; i<n; i++)
            drawing_[i] = new shape();
  }

---

but after the line: drawing_ = new pshape[n]; the program returns to main()
without entering the for loop;
so I tried this instead:

Code:

---

Drawing(int n=10) :size_(n)
  {
        pshape* temp;
      temp = new pshape[n];
      if (temp==NULL) exit(-1);
        for (int i=0; i<n; i++)
        {
              temp = new shape();
              if (temp[i]==NULL) exit(-1);
        }
      drawing_=temp;
  }

---

and this time it returns to main right after pshape* temp;
what wrong with the code?

I think I solved it.
I moved the implementation to the .C file and it worked.....

Um? I think you are either misinterpreting what you are seeing in the debugger, or you have a problem elsewhere and shuffling code around simply moved the place where bad things start to happen to some other part of the code.

If you don't understand why your changes fix things, chances are the problem is not fixed, just modified.

In any case, I don't think that pointer typedefs like that make code any clearer (on the contrary), you should be using std::vector instead of dynamically allocated array, and shared_ptr (available in boost or compilers which support this C++0x addition) instead of naked pointers to single objects (or perhaps boost::ptr_vector).

Can't use STL.....

this was my class declaration (Drawing.H):

Code:

---

class Drawing{
private:
 shape** drawing_;
 int size_;
public:
 Drawing(int n=10) :size_(n)
  {
        drawing_ = new shape*[n];
        for (int i=0; i<n; i++)
              drawing_[i] = new shape();
  }
...
};

---

when I changed it to:

Code:

---

class Drawing{
private:
 shape** drawing_;
 int size_;
public:
 Drawing(int n=10) ;
...
};

---

and added this to the Drawing.C file:

Code:

---

Drawing::Drawing(int n) :size_(n)
  {
        drawing_ = new shape*[n];
        for (int i=0; i<n; i++)
              drawing_[i] = new shape();
  }

---

suddenly everything worked.....

Perhaps it was a rebuild of the project that helped, or you still have a problem elsewhere which has now moved (for example because the constructor is no longer inlined), since changes like this don't fix real problems.

BTW, if this is C++ code, shouldn't it be Drawing.cpp?

I'm working in Unix....

That should not change the fact that .cpp is a valid extension (and perhaps the or one of the most famous extensions for C++ code files).

Quote:

---

Originally Posted by Elysia

That should not change the fact that .cpp is a valid extension

---

Yes, but the point is that .C is a valid extension for a C++ source file, contrary to what cpjust implied. I would recommend .cpp over .C because of the reduced potential for confusion and that it will not cause problems even when the file names are case insensitive.

Quote:

---

Originally Posted by laserlight

Yes, but the point is that .C is a valid extension for a C++ source file, contrary to what cpjust implied. I would recommend .cpp over .C because of the reduced potential for confusion and that it will not cause problems even when the file names are case insensitive.

---

True, true, but it doesn't change the fact that .cpp is a valid extension in Unix, as well, and can be used, if one would want to!
Just because it's Unix doesn't mean .cpp is a non-valid extension, so the reply...

Quote:

---

Originally Posted by stewie griffin

I'm working in Unix....

---

...was a bad one and had to be responded to ^_^

stewie griffin was saying that .C is a valid cpp extension in Unix, therefore it is fine for him to use it. I still recommend using .cpp, but whatever.

It has been a long while since I used the compiler so I may be wrong, but didn't one of the Sun compilers require the extension to be '.C'?

O_o

Soma

Oh my goodness... No...
How moronic would that be...?
Isn't .cpp de-facto standard for C++ source files?

Quote:

---

Originally Posted by Elysia

Isn't .cpp de-facto standard for C++ source files?

---

No, it is not. I believe that .cc and .cxx are also quite popular.

Mmm, how about one of the de-facto standards? A popular one, to be sure, no?

Quote:

---

Originally Posted by Elysia

Mmm, how about one of the de-facto standards? A popular one, to be sure, no?

---

Definitely, but we are detracting from the issue that cpjust brought up which was tangentially related to the thread.