Class template for numeric types

Question

How do I write a class template that accepts only numeric types (int, double, float, etc.) as template?

Answer 1

I found the error messages received from the template approach highly cryptic (VS 2015), but found that a static_assert with the same type trait also works and lets me specify an error message:

#include 

template 
struct S
{
    static_assert(std::is_arithmetic::value, "NumericType must be numeric");
};

template 
NumericType add_one(NumericType n)
{
    static_assert(std::is_arithmetic::value, "NumericType must be numeric");
    return n + 1;
}

int main()
{
    S i;
    S s; //doesn't compile

    add_one(1.f);
    add_one("hi there"); //doesn't compile
}