Is it possible to print a variable's type in standard C++?

Question

For example:

int a = 12;
cout << typeof(a) << endl;

Expected output:

int

Answer 1

You could use a traits class for this. Something like:

#include 
using namespace std;

template  class type_name {
public:
    static const char *name;
};

#define DECLARE_TYPE_NAME(x) template<> const char *type_name::name = #x;
#define GET_TYPE_NAME(x) (type_name::name)

DECLARE_TYPE_NAME(int);

int main()
{
    int a = 12;
    cout << GET_TYPE_NAME(a) << endl;
}

The DECLARE_TYPE_NAME define exists to make your life easier in declaring this traits class for all the types you expect to need.

This might be more useful than the solutions involving typeid because you get to control the output. For example, using typeid for long long on my compiler gives "x".