#include <iostream>
using namespace std ;
void func ( int * p ) ;
int main()
{ int x = 20 ;
func( &x ) ;
cout << "x = " << x << endl ;
}
void func ( int * p )
{ int a = 10 ;
*p += a ;
p = &a;
*p = *p + a ;
cout << "*p = " << *p << endl ;
cout << "a = " << a << endl ;
}

int a = 10 ;
*p += a ;
所以 x 为 30