c++classelaborated-type-specifier

When I should add the word "class" creating pointer in C++?

In what cases it could be invalid to write Type *p = nullptr;

whereas only class Type *p = nullptr; is satisfying?

Solution

  • You need it when the type Type is shadowed by the name of a variable:

    class Type{};

int main() {
    int Type = 42;

    //Type * p = nullptr; // error: 'p' was not declared in this scope
    class Type* p = nullptr;
}

    However, as pointed out by Ayxan Haqverdili, ::Type* p = nullptr; works as well and has the added benefit of also working with type aliases.