difference between *p and p*

Question

if p=3
*p= //value
p*= //value

Answer 1

It's different operators.
"*p=?" will write what you wrote for "?" to address 3 in memory, if your operating system let's you access it (assuming p is a pointer). The * operator dereferences the pointer p and the = operator assigns a new value to that position in memory.
"*=?" is a single operator that means in context of p "p = p * ?" ("?" needs to be filled in by a number)

Answer 2

if *p is pointer variable then what is value?

Answer 3

Hi Privanshu, it's the data that is in your memory on address 3. If p is a pointer to int (int*) the data at this memory address will be interpreted as an integer number, if it's a pointer to double, it's interpreted as a double and so on...