Struct/typedefs

[Wynd]

I have seen code like this in some places:

typedef struct _mystruct {
    int x;
    int y;
} mystruct;

But, in my C++ class at school, the teacher told us to do it like this (no typedef):

struct mystruct {
    int x;
    int y;
};

Why would you do the first one if the second one works?