C++ function to output generic struct

Question

I would like to know how to write a C++ function to print the attributes of a generic struct. For example,

struct a {
std::string field_1;
std::string field_2;
std::string field_3;
};


struct b {
int a;
int b;
int c;
};

The function would take struct of form 'a' or 'b'as inputs and generate outputs. Perhaps a template could be used -- if so how would one build it?

score 2 · Answer 1 · answered May 11 '16 at 01:57

2

This is not possible in standard C++, it does not work this way. C++ does not have reflection.

answered May 11 '16 at 01:57

Sam Varshavchik

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This wouldn't be too difficult in Java. Surprised it's not possible in C++ – K Alistair May 11 '16 at 02:13
@KAlistair Indeed, but Java and C++ are actually very different – kmdreko May 11 '16 at 02:21
Java is a managed language. C++ is not. Managed languages are fundamentally different from natively-compiled languages, like C++. – Sam Varshavchik May 11 '16 at 02:22

score 1 · Answer 2 · edited May 23 '17 at 12:33

1

This is currently not possible but might be available in C++17 with static reflection.

See also Compile-time reflection in C++1z?

edited May 23 '17 at 12:33

Community

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answered May 11 '16 at 02:19

Henricus V.

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score 0 · Answer 3 · answered Jan 31 '17 at 13:56

There are two possibilities to work around the missing support for reflections in c++.

The first one is to use std::tuple instead and iterate over it. This can be done explicitly by reflection or nicely wrapped in boost::fusion.

The second posibillity with c++14 is boost::hana. In boost::hana there are structs, that can be iterated over. This is done with the help of preprocessor macros.

If you are still interested, i can post a minimal example here.

C++ function to output generic struct

3 Answers3