Missing Type Specifier Error (I specified std::string_view, though)

Question

I have this project that I made following an example code listing in my C++20 book. I have a whole bunch of compiler errors, though, first of which is this:

1>E:\programming\visual_studio_2019\Projects\beginningcpp20\Ex13_01\Ex13_01\Ex13_01.cpp(17,20): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

I don't have any missing type specifiers on that line, nor are there really any syntax errors anywhere in the file. How do I fix this error?

Answer 1

A couple of typo errors where the class name box (lower case 'b') was used instead of Box in Ex13_01.cpp.

void show(const box& box1, std::string_view relationship, const Box& box2);

void show(const box& box1, std::string_view relationship, const Box& box2)
{
...
}

also in Box.ixx

    bool operator==(const Box& other_box)

instead of 

    bool operator==(const Box& other_box) const