C pointer declaration

int* ptr;
int * ptr;
int *ptr;

pick one;

>>1
The middle one because it looks nice with the spacing style of K&R (e.g., a + b or a != b).

>>6
Out of these three, only int *ptr makes any sense.
That is true but the asterisk used for declaration should be different from the asterisk used for dereferencing. It's more clear that way.

int * a;
int b;
a = &b;
*a = 5;