Benefits of pointers?

Question

I recently developed an interest in C programming so I got myself a book (K&R) and started studying.

Coming from a University course in Java (basics), pointers a

Answer 1

In this example:

int f1(int i); 
f1(x);

the parameter i is passed by value, so the function f1 could not change the value of variable x of the caller.

But in this case:

int f2(int* i);
int x;
int* px = &x;
f2(px);

Here we still pass px parameter by value, but in the same time we pass x by refference!. So if the callee (f2) will change its int* i it will have no effect on px in the caller. However, by changing *i the callee will change the value of x in the caller.