what is the difference between *++p, ++*p, and *p++

Answer 1

The expression ++*p has two operators of same precedence, so compiler looks for assoiativity. Associativity of operators is right to left. Therefore the expression is treated as ++(*p).

The expression *p++ is treated as *(p++) as the precedence of postfix ++ is higher than *.

The expression *++p has two operators of same precedence, so compiler looks for assoiativity. Associativity of operators is right to left. Therefore the expression is treated as *(++p).

*p++ : post increment a pointer p
++*p : pre increment the value at p location
*++p : pre increment a pointer p

so,
*p++ is equivalent to *(p++)
++*p is equivalent to ++(*p)
*++p is equivalent to *(++p)

Answer 2

*++p is evaluated as *(++p). It increments the value of p before dereferencing it.

++*p is evaluated as ++(*p). It dereferences p, and then increments it.

*p++ is evaluated as *(p++). The value of p is returned to the expression before being incremented, and then p is dereferenced.

http://en.cppreference.com/w/cpp/language/operator_precedence

Answer 3

thanku to all of u