working with file name [] ???

[rox]

beginner confused here:

FILE* functionName(char [])

where i pass a string as the file name, open the file and return fp.

how do i work with the passed string? Should i have a name[] string so i have a name to work with or how does this work? i've never seen this before.

Thank for the help !!!

[okinrus]

What you can do is something like this
FILE* functionName(char* name) or
FILE* functionName(char name[])

If your not modifying the string you can do
FILE* functionName(const char* name)

What happens is that the array of characters containing the filename decays into a char pointer, which points to the beginning of the array, when passing it through function.

[Prelude]

>how do i work with the passed string?
The same way you normally do. Since C++ passes arrays as a pointer to the first element, you have a pointer to work with. However, the type of the pointer is not const, so you can assume that it's modifiable. Though I don't see you needing to change it in this function:

FILE *open_reading ( char filename[] )
{
  FILE *rin = fopen ( filename, "r" );

  if ( rin == NULL )
    // Do something intelligent

  return rin;
}

[rox]

Thank, so my suspicion was right.

Problem was, i got some function definition given, and until now i was using them the way they were given. Now they only gave me :

FILE* fuctionName(char [])

and i wasn't sure how to reference to my passed string.

FILE* functionName(char name[])

this sound like what i wanted. Thanks.

[Prelude]

You were given a prototype. The name of a parameter is optional in prototypes, hence the funny "char []" syntax. That is simply the parameter with no name.

[rox]

great, thank Prelude. Now it makes sense.

Couldn't they put that info in the book too? grr.