如何在模板类C ++中使用具有多个参数的模板函数

Question

I'm trying to work on a question for a project in class where our data structures and methods are already pre-defined. It's my job to implement some functions that use these templates.

For example, I'm supposed to create a follows function, that does this: if I did follows(q) where q = {"h", "e", "l", "l", "o", "w", "r"} and q is of type ArrayQueue , it would create an ArrayMap that holds a single queue value as a key and a set of values that is next to that queue value.

If I looked inside the map, it would look like this:

Key -> Set Containing the Values
h -> set[e]
e -> set[l]
l -> set[l, o]
o -> set[w]
w -> set[r]

Now, I'm supposed to implement this function by using this template signature:

template<class T>
ics::ArrayMap<T,ics::ArraySet<T>> follows (const ics::ArrayQueue<T>& q) 
{
}

Although I understand the general logic behind how I would do this, I do need one thing: to be able to access and update the second parameter in the returned ArrayMap , which is ics::ArraySet<T>

So how would I call this ArraySet as a variable to do modifications on?

Answer 1

From your description it sounds like you should be able to do the following:

ics::ArraySet<T>& followers = the_array_map[x];

Assuming that you have a variable the_array_map which holds the follower map that you are constructing (and returning from the function).

Now you can update followers by appending the desired element to it.