Define multiple private functions with same return type and parameters type in one line

Question

I'm totally new to C++ and I was wondering if there's a way to define n functions which have same return type and parameters type in a single line in order to maintain a DRY code.

I tried looking for a solution online and on SO but I wasn't able to find a proper answer.

myHeader.h

class MyClass{

public:
    . . .

private:
    . . .
    std::vector<Dcel::Vertex*> addVertices(std::vector <Dcel::Vertex*>);
    std::vector<Dcel::Vertex*> randomPointsGetter(std::vector<Dcel::Vertex*>);
};

For instance, they both return std::vector<Dcel::Vertex*> type and take std::vector <Dcel::Vertex*> as parameters input.

Is it possible to define both of them, or n functions, in the same line? If yes, How?

Thanks in advance.

Answer 1

Is it possible to define both of them, or n functions, in the same line? If yes, How?

All whitespace is treated equally in C++, so sure. Here are two functions declared in the same line:

T function(); T another_function();

If you meant whether you could declare multiple functions in one full-expression, or "share" the return type, then no, that is not possible.

---

If you dislike the complexity of repeated std::vector<Dcel::Vertex*> , you can use an alias:

using R = std::vector<Dcel::Vertex*>;
R addVertices(R);
R randomPointsGetter(R);

Edit: This using declaration is semantically equivalent with typedef as shown in Josh Kelley's answer.

Answer 2

Using a typedef helps cut down on duplication, although it still doesn't let you define multiple functions on the same line.

typedef std::vector<Dcel::Vertex*> VertexList;

VertexList addVertices(VertexList);
VertexList randomPointsGetter(VertexList);

Answer 3

When the number of functions grows, a macro seems appropriate:

class MyClass {

#define MY_PREFIX_DECL_FN(name) \
    std::vector<Dcel::Vertex*> name(std::vector<Dcel::Vertex*>)

    MY_PREFIX_DECL_FN(addVertices);
    MY_PREFIX_DECL_FN(randomPointsGetter);
    MY_PREFIX_DECL_FN(...);

#undef MY_PREFIX_DECL_FN

};

Answer 4

Yes.

You can define N functions either using std::vector or std::array :

std::vector< std::function(std::vector<Dcel::Vertex*>(std::vector <Dcel::Vertex*>)) > my_private_functions;
std::array< std::function(std::vector<Dcel::Vertex*>(std::vector <Dcel::Vertex*>)),N > my_private_functions;