Questions about dynamic memory allocation * What does the following operation do? int *p; p = new int(4); * What does the following operation do? delete pn; * What does the following operation do? int *p; p = new int[20]; * What does the following operation do? delete [] p; * is there a problem with this code? if yes, what is the name of this problem? delete p; *p=2; * is there s problem with this code? if yes, what is the name of this problem? int *p=new int(3); p=new int(4);