what is the size of an enum type data in C++?

Question

This is a C++ interview test question not homework.

#include 
using namespace std;
enum months_t { january, february, march, april, may, jun         


        

Answer 1

The size is four bytes because the enum is stored as an int. With only 12 values, you really only need 4 bits, but 32 bit machines process 32 bit quantities more efficiently than smaller quantities.

0 0 0 0  January
0 0 0 1  February
0 0 1 0  March
0 0 1 1  April
0 1 0 0  May
0 1 0 1  June
0 1 1 0  July
0 1 1 1  August
1 0 0 0  September
1 0 0 1  October
1 0 1 0  November
1 0 1 1  December
1 1 0 0  ** unused **
1 1 0 1  ** unused **
1 1 1 0  ** unused **
1 1 1 1  ** unused **

Without enums, you might be tempted to use raw integers to represent the months. That would work and be efficient, but it would make your code hard to read. With enums, you get efficient storage and readability.