I really need help with this one...
1.) Look at the following declaration.
enum Person { BILL, JOHN, CLAIRE, BOB };
Person p;
Indicate which of the following statements or expressions is valid.
A.) p = BOB;
B.) p++;
C.) BILL > BOB
D.) p = 0;
E.) int x = BILL;
F.) p = static_cast<Person>(3);
G.) cout << CLAIRE << endl;
To determine which of the statements or expressions are valid, we need to understand the concept of an enumeration (enum) and how it works.
An enum is a user-defined type that consists of a set of named constants called enumerators. In this case, the enum "Person" has four enumerators: BILL, JOHN, CLAIRE, and BOB. These enumerators are internally represented by integer values, starting from 0 by default, and incremented by 1 for each subsequent enumerator.
Now let's analyze each statement or expression to determine if it is valid:
A.) p = BOB;
The enum Person is an integral type, so it is valid to assign one of its enumerators (BOB) to a variable of type Person (p).
B.) p++;
The expression p++ attempts to increment the value of p. Since Person is an enum, it is not valid to use the "++" operator directly on the enum variable. Enums do not support arithmetic operations like increment or decrement.
C.) BILL > BOB;
This expression compares the enumerators BILL and BOB using the ">" operator. The comparison operators are valid for enum types, so this statement is valid.
D.) p = 0;
Since the enumerators of the enum Person are not assigned explicit integer values, assigning 0 to p is not valid because 0 does not correspond to any of the enumerators.
E.) int x = BILL;
This statement attempts to assign the enumerator BILL to an integer variable x. The assignment is not valid because enum types cannot be implicitly converted to integer types. You need to use a cast to explicitly convert it.
F.) p = static_cast<Person>(3);
Here, static_cast is used to explicitly convert the integer 3 to the enum type Person. This statement is valid.
G.) cout << CLAIRE << endl;
Since the enumerators of an enum are treated as constant integer values, it is valid to print them using the cout statement.
So, the valid statements or expressions are:
A.) p = BOB;
C.) BILL > BOB
F.) p = static_cast<Person>(3);
G.) cout << CLAIRE << endl;
I hope this helps! Let me know if you have any further questions.