problem with structure

Question

3.00/5 (4 votes)

See more:

what is meaning of this?

C++

struct texture
{
    unsigned char r[10];
};

struct texarray
{
    texture mode[1];
};

we have one structure with a member as a member of an other structure.
I don't understand the meaning of it?
could you explain for me with an example, please?

Posted 19-Oct-12 4:13am

ssssdaaads

Updated 19-Oct-12 6:11am

armagedescu

v4

Add a Solution

Comments

Keith Barrow 19-Oct-12 10:46am

No, I don't understand it either. Unless there is something subtle and c++y going on (I'm a c# dev with a little c++ experience about 10 years ago) I doubt the code above is well written. Might be worth trawling through the code and seeing where it is used to see what it is intended for.

Sergey Chepurin 19-Oct-12 12:19pm

And why this question has been downvoted???

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Stefan_Lang · Answer 1 · 2012-10-19T06:08:00

This may be a common trick used in C programming, but it's hard to tell without seeing the context it is used in. I am referring to the practice of allocating a struct with arbitrary number of elements dynamically without need to treat it as a pointer, or the overhead of even having a pointer:

C++

texarray* foo(std::size_t sz) {
   texarray* pta = reinterpret_cast<texarray*>(new texture[sz]);
   for (std::size_t i = 0; i < sz; ++i) {
      strcpy(pta->mode[i], "undefined");
   }
   return pta;
}
void bar(textarray* pta) {
   delete [] reinterpret_cast<texture*>(pta);
}

int main() {
   textarray* p = foo(15);
   // now do something with it
   // ...

   // and release again:
   bar(p);
   return 0;
}

Note that this trick usually requires a special function to release the memory correctly again, or else you'll end up with memory leaks or, worse, run-time errors.

Richard MacCutchan · Answer 2 · 2012-10-19T05:29:00

C++

// this structure contains up to 10
// characters in the array named r
struct texture
{
    unsigned char r[10]
}
// this structure contains up to 1
// texture structures in the array
// named mode
struct texarray
{
    texture mode[1]
}

However, the definition mode[1] allows the developer to allocate larger, variable length arrays (using new or malloc()) which can then handle different amounts of data. This is a useful way of defining a structure when it is not known, at compile time, exactly how many elements may be needed, or presented when reading variable length data.

problem with structure

2 solutions

Solution 2

Solution 1

Add your solution here

Preview 0