Class module example

[duggie]

Can someone please explain the differences between the two pieces of code below.

Code 1 declares NormalHrs and OverHrs as PRIVATE and so introduces EmpNormalHrs and EmpOverTimeHrs but is that really necessary?

In code 2, NormalHrs and OverHrs are declared PUBLIC and there is no need to introduce EmpNormalHrs and EmpOverTimeHrs, yet it works equally well?

Thanks in advance.

[COLOR="SeaGreen"]'***** Code 1[/COLOR]
[COLOR="SeaGreen"]'***** This is entered into a class module, named clsEmployee[/COLOR]
[COLOR="Navy"]Public[/COLOR] EmpName [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]String[/COLOR]
[COLOR="Navy"]Public[/COLOR] EmpRate [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
[COLOR="Navy"]Private[/COLOR] NormalHrs [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
[COLOR="Navy"]Private[/COLOR] OverHrs [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]

[COLOR="Navy"]Property[/COLOR] [COLOR="Navy"]Let[/COLOR] EmpWeeklyHrs(Hrs [COLOR="Navy"]As[/COLOR] Double)
    NormalHrs = WorksheetFunction.Min(35, Hrs)
    OverHrs = WorksheetFunction.Max(0, Hrs - 35)
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Property[/COLOR]
[COLOR="Navy"]Property[/COLOR] [COLOR="Navy"]Get[/COLOR] EmpWeeklyHrs() [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
    EmpWeeklyHrs = NormalHrs + OverHrs
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Property[/COLOR]
[COLOR="Navy"]Property[/COLOR] [COLOR="Navy"]Get[/COLOR] EmpNormalHrs() [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
    EmpNormalHrs = NormalHrs
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Property[/COLOR]
[COLOR="Navy"]Property[/COLOR] [COLOR="Navy"]Get[/COLOR] EmpOverTimeHrs() [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
    EmpOverTimeHrs = OverHrs
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Property[/COLOR]
[COLOR="Navy"]Public[/COLOR] [COLOR="Navy"]Function[/COLOR] EmpWeeklyPay() [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
    EmpWeeklyPay = (EmpNormalHrs * EmpRate) + (EmpOverTimeHrs * EmpRate * 2)
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Function[/COLOR]


[COLOR="SeaGreen"]'***** This is entered into a standard module[/COLOR]
[COLOR="Navy"]Sub[/COLOR] EmpPayOverTime()
[COLOR="Navy"]Dim[/COLOR] Employee [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]New[/COLOR] clsEmployee
    [COLOR="Navy"]With[/COLOR] Employee
        .EmpName = "Joe Bloggs"
        .EmpRate = 100
        .EmpWeeklyHrs = 45
        MsgBox .EmpName & Chr(10) & Chr(9) & _
        "Normal Hours: " & .EmpNormalHrs & Chr(10) & Chr(9) & _
        "OverTime Hours: " & .EmpOverTimeHrs & Chr(10) & Chr(9) & _
        "Weekly Pay : $" & .EmpWeeklyPay
    [COLOR="Navy"]End[/COLOR] [COLOR="Navy"]With[/COLOR]
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Sub[/COLOR]

[COLOR="SeaGreen"]'***** Code 2[/COLOR]
[COLOR="SeaGreen"]'***** This is entered into a class module, named clsEmployee[/COLOR]
[COLOR="Navy"]Public[/COLOR] EmpName [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]String[/COLOR]
[COLOR="Navy"]Public[/COLOR] EmpRate [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
[COLOR="Navy"]Public[/COLOR] NormalHrs [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
[COLOR="Navy"]Public[/COLOR] OverHrs [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]

[COLOR="Navy"]Property[/COLOR] [COLOR="Navy"]Let[/COLOR] EmpWeeklyHrs(Hrs [COLOR="Navy"]As[/COLOR] Double)
    NormalHrs = WorksheetFunction.Min(35, Hrs)
    OverHrs = WorksheetFunction.Max(0, Hrs - 35)
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Property[/COLOR]
[COLOR="Navy"]Property[/COLOR] [COLOR="Navy"]Get[/COLOR] EmpWeeklyHrs() [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
    EmpWeeklyHrs = NormalHrs + OverHrs
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Property[/COLOR]
[COLOR="Navy"]Public[/COLOR] [COLOR="Navy"]Function[/COLOR] EmpWeeklyPay() [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]Double[/COLOR]
    EmpWeeklyPay = (NormalHrs * EmpRate) + (OverHrs * EmpRate * 2)
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Function[/COLOR]


[COLOR="SeaGreen"]'***** This is entered into a standard module[/COLOR]
[COLOR="Navy"]Sub[/COLOR] EmpPayOverTime()
[COLOR="Navy"]Dim[/COLOR] Employee [COLOR="Navy"]As[/COLOR] [COLOR="Navy"]New[/COLOR] clsEmployee
    [COLOR="Navy"]With[/COLOR] Employee
        .EmpName = "Joe Bloggs"
        .EmpRate = 100
        .EmpWeeklyHrs = 45
        MsgBox .EmpName & Chr(10) & Chr(9) & _
        "Normal Hours: " & .NormalHrs & Chr(10) & Chr(9) & _
        "OverTime Hours: " & .OverHrs & Chr(10) & Chr(9) & _
        "Weekly Pay : $" & .EmpWeeklyPay
    [COLOR="Navy"]End[/COLOR] [COLOR="Navy"]With[/COLOR]
[COLOR="Navy"]End[/COLOR] [COLOR="Navy"]Sub[/COLOR]

 

[GTO]

Could you provide a link to where you copied the code from?

FYI: When posting code, you can use code tags:

[code=rich] '...your code here[/code]

 

[duggie]

Afraid cannot find a link.

 

[xenou]

It's really a matter of variable scope. Variables with public scope (also called global scope) can be accessed outside of their class or modules. Variables with private scope can be accessed only inside their class or module. So if you have private variables, one way to "provide" access to them is through a public property or public method.

I use private variables much more than public ones. I almost never use public variables. This keeps the class more organized and forces you to think about how and why you want to give access to class variables. Using class properties is also better on the client side since properties are easy to work with using class - dot - property notation.