有什么区别：使用关键字 struct 在相同类型的结构内创建结构指针

Question

Coming from a C++ background here. I'm required to write C for my one of my courses, which I've never been exposed to. What's' the difference beteween these two declarations? Why include the struct keyword? Are there different meanings? Do they have different meanings in C++ vs C?

struct A {
    int dataA;
    A* nextA;
};

struct B {
    int dataB;
    struct B* nextB;
};

The comments below say that the first is invalid in C. However, I'm compiling just fine with gcc.

Edit: I was compiling a .cpp file with gcc. I'm such a noob lol.

Solution: The the second is required for C where the first is only valid in C++.

Answer 1

struct B {
    int dataB;
    B* nextB;
};

is the same as

struct B {
    int dataB;
    struct B* nextB;
};

in C++ but not in C. When using C, you'll have to use the second form. The first form is not legal C.