What is the advantage of creating constants in enum as opposed to creating each variable individually with the same value?

Also, what is meant by using enum as a label?

Yes what the person above me said is correct.  If you have a set of related named constants it makes your code a lot more readable to define them all in the same place and in the same way using an enum. 

For the following example I will used the days of the week as constants. You could just internally represent each day with integer values from 0 ~ 6.  I might make a switch statement like this

int day = some day value;

switch (day) {
case 0: do something for monday; break;
case 1: do something for tuesday; break;
...
case 6: do something for sunday: break;
}

This is ok... but I could have used named constants to make the code a bit more readable

Option 1: normal constants

const int MONDAY = 0;
const int TUESDAY = 1;
...
const int SUNDAY = 6;

Option 2: Using an enum

enum Days {MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY}

Now with either option my switch statement becomes

switch (day) {
case MONDAY: do something for monday; break;
case TUESDAY: do something for tuesday; break;
...
case SUNDAY: do something for sunday: break;
}

And this is what I mean by using them as a "label".  You associate a valid identifier with a constant value in your program to make the code more readable.

Hope this helped!

Yes they are of the enum type, and no you wouldn't use Days for the switch.  Here is an example try it yourself.

#include <iostream>

int main() {
    int choice;

    enum Days {MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY};

    std::cout << "Choose a day of the week 0 - 1: ";
    std::cin >> choice;

    switch(choice) {
    case MONDAY:
        std::cout << "You chose Monday" << std::endl;
        break;
    case TUESDAY:
        std::cout << "You chose Tuesday" << std::endl;
        break;
    }
    return 0;
}