在C ++中定义模板类的默认实现

Question

I know it is possible to define default values for template parameters:

template<int N = 10> struct Foo {};

You can use this like Foo<> for example, but I want to be able to write just Foo .

I tried the following, but it doesn't work (throws compiler exception):

struct Foo : Foo<10> {};

Is this possible in C++?

Answer 1

You can't directly, but can achieve something close thanks to a typedef , ie

template<int N = 10> struct Foo{};

typedef Foo<> DefaultFoo;//Or whatever name that fits, just not 'Foo'

int main() {
    DefaultFoo myFoo;
    return 0;
}