int*p=&var ---- what is this????

Answer 1

It is simply example of declaring and initialising a pointer at the same time , it shortens the code size.

Int var;
Int *ptr ;
ptr = &var ;

Or simply you can write
Int var;
Int *ptr=&var ;

Answer 2

This is example if work with a pointer variable. The pointer variable does not contain any value (as number, string,..], but points to another variable (or later into dynamic variable in memory]. So the example says
int*p=&var;
declare p as pointer to integer variable
and points to variable var...

Answer 3

as Petr said, p is essentially a variable that stores the memory address of another variable.