I feel like a stupid, pointers:

Hey, I'm reading now a C++ tutorial from cprogramming.com, lesson about a structures. And I see now and example of pointers in structures:

Code:

---

#include <iostream>
using namespace std;

struct xampl { 
    int x;
};

int main()
{
  xampl structure;
  xampl *ptr;
  structure.x = 12;
  ptr = &structure;
  cout<< ptr->x;
  cin.get();                   
 }

---

And I'm confused about that part:

Code:

---

cout<< ptr->x;

---

What for do we use that, if I just can write

Code:

---

cout<<structure.x;

---

instead of the pointer?

Efficiency and clarity is what you gain when you pass pointers to a structure as parameters to a function.

Efficiency is result of not copying the structure needed by the function.

Using "->" instead of "." combined with "*" adds clarity.

In case the sentence above makes no sense to you here is an example of the wrong way from a clarity point of view.
Edit2: Forgot the () were needed.

Code:

---

cout<< (*ptr).x;

---

The normal way you posted.

Code:

---

cout<< ptr->x;

---

Example used to introduce new things are rarely the best examples of why to do something. They are normally designed to show how not why.

Tim S.

Quote:

---

Originally Posted by stahta01

Efficiency and clarity is what you gain when you pass pointers to a structure as parameters to a function.

Efficiency is result of not copying the structure needed by the function.

---

Note that in blunt's example, the opposite may be the case. For a struct as small as this (and with a trivial copy constructor), a copy may actually be more efficient than having to dereference a pointer to get at the struct's contents.