Strange warning massage

[qzou666]

Hi,

I have a function as follow:

void ClassA::FunctionA()
{
float* a
a = new float[5];
}

The Visual C++ compiler keeps giving the following warning massages:

warning C4305: 'initializing' : truncation from 'int' to 'short'
warning C4309: 'initializing' : truncation of constant value

Could anyone tell me what caused the warnings?

Thanks a lot

 

[programsecrets]

Strange warning message? Instead, I'd say, strange class. Here's what I think is happening...

void ClassA::FunctionA()
{    
  float* a
  a = new float[5];
}

You create a single variable pointer of type "float", called 'a'. Given that you've only got a single pointer, the next line should only allocate a single float object. Instead, you attempt to allocate 5. And because you don't cast the object(s) that are being created, the new operation creates integer object(s) as a default. Here's a corrected version of your class:

void ClassA::FunctionA()
{    
  float* a
  a = (float*)new float;
}

 

[programsecrets]

Now, if your intent is to create 5 float objects, then do something like this:

void ClassA::FunctionA()
{
  float* a[5];
  int i = 0;

  // initialize pointers to NULL
  for (i = 0; i < 5; i++)
  {
    a[i] = NULL;
  }

  // create float objects
  for (i = 0; i < 5; i++)
  {
    a[i] = (float*)new float;
    // you probably should be checking for
    // allocation failure; that's up to you.
  }

  // ...then use the float objects...

  // finally, don't forget to delete them
  for (i = 0; i < 5; i++)
  {
    if (a[i] != NULL)
    {
      delete (a[i]);
      a[i] = NULL;
  }
}

 

[qzou666]

Thanks, programsecrets.

I think the statement is OK since float is a basic type, not a class.

float* a; (sorry, I missed ';')
a = new float[5];

In fact, there are a large number of similar functions in the same class, and most of them do not cause the warning masssages.

Cheers.

 

[programsecrets]

Sorry for the overkill. I was just trying to think of some ideas...

I'm glad you solved your own problem.

 

[abp]

Which version of MS VC compiler are you using...

Anand ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mail me at abpillai@excite.com if you want additional help. I dont promise that I can solve your problem, but I will try my best.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

[sflam]

I don't see any problem with that code. Are you sure that is the line of the warning?

Shyan