which one are declarations and which one are definitions

Assume these statements are all outside of functions. Which of the following are declarations only and which are definitions:
float * rate ;
struct S ;
static double pi;
typedef int * string;
node * fun(int i);
extern double x;

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Let me google that for you.

Try to do your own homework (did you read the site's homework policy?). Tell us which you think are definitions and which are declarations, and why, and we will help you where you went wrong.

typedef int * string;
node * fun(int i);

are the only definition i can think off.

Others are declarations.

You failed to answer the "why" part, the part I put in bold in my post, because it's extremely important. Why do you think those two are the only definitions?

I don't know what struct S ; does. If anything.