void change(int *p)

{

*p = 100;

}

void change2(int **p)

{

*p = new int(200);

}

void change3(int *&p)

{

p = new int(300);

}

int main()

{

int a = 1;

int *b = new int(2);

change(&a); // a  = 100

change(b);  //*b  = 100

cout<<<'\t'<<*b<

delete b;

b = NULL;

change2(&b);//*b = 200

cout<<<'\t'<<*b<

delete b;

b = NULL;

change3(b); //*b = 300

cout<<<'\t'<<*b<

delete b;

b = NULL;

return 1;

}