Question

I had come across the following code:

typedef struct {
        double x;
        double y;
        double z;
} *vector;

Is this a valid type definition? The code compiles and runs fine. I was just curious if this is common practice.

Answer 1

Absolutely valid.
Usually, you can take full advantage of this way by defining two types together:

typedef struct
{
 int a;
 int b;
} S1, *S1PTR;

Where S1 is a struct and S1PTR is the pointer to this struct.