What is the effect of the following statements? If a statement is invalid, explain why it...

What is the effect of the following statements? If a statement is invalid, explain why it is invalid. The classes stackADT , stackType , and linkedStackType are as defined in this chapter.

a. stackADT newStack;

b. stackType sales(−10);

c. stackType names;

d. linkedStackType numStack(50);