Namespace friend functions C++

[shwanky]

So I have this Class Random that needs to have a friend function sort which needs to exist in two namespaces.

Class Random
{
... Some stuff
friend void sort(Random &x);
}

namespace ascending
{
void sord(Random &x)
{
... Some Stuff
}
}

namespace descending
{
void sort(Random &x)
{
... Some Stuff
}
}


The problem is I need sort to be able to access the private members of the Random class but to define sort I need to have the namespaces ascending and descending already declared... Its a weird circular argument that can't work. My question is, how can I define the Class Random with so that it can have a friend function sort that resides in two namespaces?

 

[sennyk]

I think that you can do the following.

class Random;

namespace ascending
{
void sort(Random* x)
{
...
}
}

namespace descending
{
void sort(Random* x)
{
...
}
}

class Random
{
friend void ascending::sort(Random* x);
friend void descending::sort(Random* x);
...
};

I think that will work; however, I haven't tried it. You may also be able to do the same sort of thing using templates instead of the forward declaration and pointer usage.

Ken

 

[ravenprp]

One solution to this problem could be to declare the friend function sort as a member of the Random class instead of making it a friend function. This way, the function will have access to the private members of the class without the need for namespaces. However, if you still want to keep the function as a friend function, you could declare it as a friend function of both namespaces by using the syntax: "friend void ascending::sort(Random &x)" and "friend void descending::sort(Random &x)". This way, the function will have access to the private members of the Random class and can be defined separately in each namespace. Another option could be to use a using declaration inside the namespaces, so that the friend function can be accessed without specifying the namespace. For example, "using ascending::sort;" and "using descending::sort;" would allow you to simply call "sort(x);" inside the Random class without specifying the namespace. Overall, the solution will depend on your specific needs and preferences.