Struct prototype

Hey guys

I never use structs really but I was messing around with them and I discovered somthing that my book doesnt teach. The below code will not compile as I havent declared a prototype for the "printNumber" function, but that made me think, what parameter do I place in the prototype to suggest I will be passing a struct to it? I havent covered passing objects to functions yet, so I thought id try with structs before I attempted classes.

And, is it safer to pass it by reference or pointer reference?

Code:

---

#include <iostream>

struct Number
{
  int m_Num;
};

int main()
{
    Number n;
   
    n.m_Num = 10;
   
    printNumber ( n );
   
    std::cin.get();
   
    return 0;
}

void printNumber ( Number passStruct )
{
    std::cout << "Number was: " << passStruct.m_Num;
}

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Any help appriciated :)

I generally just copy the text between the return type and just before the { that defines the body of the function, then add a semicolon. So like this:

Code:

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void printNumber ( Number passStruct );

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You can omit the parameter passStruct, so this is valid:

Code:

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void printNumber ( Number );

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But the only side-effect of this that you don't know what the parameter is supposed to stand for, e.g.

Code:

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void myfunc(int, int)

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says much less than

Code:

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void myfunc(int id, int age)

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--
Mats

Thanks mats. Very helpful.

Also, as they say, references are the "C++ way" of passing data. If you can avoid pointers, then it's best to do so.
And to add to mats, I would use a full prototype (ie, don't leave out argument names) because everyone looking over those prototypes want to see the names and some tools such as intellisense extracts information from the prototypes, so it's always a good thing to leave them in there!

Quote:

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Originally Posted by Elysia

If you can avoid pointers, then it's best to do so.

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That statement is just asking for an argument.

Oh? Pointers do have their use, but for passing things over functions, references are preferred before pointers. And I suppose that's all.

Quote:

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references are the "C++ way" of passing data

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That's another statement just asking for an argument.

The C++ way of passing data is "by value", "by reference", or "by pointer". Which you use is situation-dependent, but saying that one of them is the "C++ way" is just wrong.