Thread: Optional Function Parameters in Prototypes

use = after the parameter with the default value, this way if the parameter is missing when called this default value will be used, example:

Code:

#include<iostream>

int stuff(int a=3);

int main()
{
	std::cout<< stuff();
}


int stuff(int a)
{
	return a;
}

prints 3. hope this helps

I believe you want null not NULL

EDIT: Just tested it, hmm odd.

NULL is defined in windef.h (which you get if you include windows.h) I agree though, 0 is what the MinGW implementation of Win32 API defines it as...

Code:

#ifndef NULL
#ifdef __cplusplus
#define NULL 0
#else
#define NULL ((void*)0)
#endif
#endif

I don't have Win SDK from MS installed on this computer so I can't check what MS defines it as, but I will assume it is simular.

windef??? NULL is defined in cstddef and cstdlib. That it works when including iostream is just coincidence.

Or just use the number 0. It works the same in C++.

Ahh, well it may be defined there too, I just know it was defined in the windows headers. I used Code::Blocks find declaration feature (I <3 it)

The most appropriate if you need NULL is <cstddef>. <iostream> is inappropriate.

Originally Posted by nadroj

i get error if i try and reference NULL, however when iostream is included it works..since this is a popular header its not a bad idea to include this if it solves the problem.

The easiest solution is to #include <cstddef> in the header file.