[Tutorial] Records

[wtd]

dodge_tomahawk wrote:

i think he means it would be easier

No, it isn't.

It makes it much harder to make adjustments to a program.

[Andy]

true, but much easier to program it rite the first time

[wtd]

dodge_tomahawk wrote:

true, but much easier to program it rite the first time

Doing things the wrong way is not a path to doing things the right way.

It just reinforces bad habits, and makes it ultimately harder to adopt a correct approach to programming.

[Andy]

its hard to start nailing oop if they have no basic tho...

[wtd]

Object-oriented programming isn't even the issue here. Good, structured programming is. Before students even begin to think about object-oriented programming they have to understand the concept of an interface... the proverbial "black box".

What you're suggesting is the roots of "spaghetti code".

[Andy]

no what im trying to say is.. they may not understand the importance of passing it through as a parameter, and resulting the object instead of just making it global...

[wtd]

So make them learn a bunch of bad habits so they can see the beauty of doing it the right way?

I can get behind that, except that CS classes move slowly enough already, and it takes time to unlearn all of the bad habits.

[gnarky]

Ok im pretty new at this.

code:

type userData:     record         Username: string         Password: string     end record     var user : array 1..1400 of userData     var username:string     get username        user(1).Username:=username     var temp : string := "temp.txt" var fileNo : int open : fileNo, temp, put put : fileNo, userData close : fileNo

A couple questions:

It says that expression is not a variable when I try to run it. What does that mean? It highlights the second last line.

Also, how do I make it so that a user inputs his/her own data without writing over someone else's.

[Andy]

userData is a type... you stilll have to declare a variable like var user:userData

[Cervantes]

Or you could go

code:

var userData :    record        %lots of stuff    end record

Depending on what you want to do with userData, that may or may not be better.
Also, when you say user inputs his/her own data... do you mean on screen, or to a file, or something else?

[gnarky]

ok...Ive got what I want to do...But I know, somehow, someway, there's an easier was to do this. Something with arrays would probably make it easier. Hope you can help me out.

code:

type userData :     record         Username : string         Password : string         Lines : string     end record var user : array 1 .. 1400 of userData var username, password, confirm : string var lines := "--------------" loop     put "Enter desired username: " ..     get username     user (1).Username := username     cls     put "Desired password: " ..     get password     user (1).Password := password     user (1).Lines := lines     var temp : string := "temp.txt"     var stream : int     open : stream, temp, put     put : stream, user (1).Lines     put : stream, user (1).Username     put : stream, user (1).Password     put : stream, user (1).Lines     close : stream     cls     put "-------------"     put "Username: " ..     put user (1).Username     put "Password: " ..     put user (1).Password     put "-------------"     put "Confirm? (Y/N)"     get confirm     if confirm = "y" then         exit     else         cls         File.Copy ("blank.txt", "temp.txt")         put "Data erased."     end if end loop cls put "Data successful entered into the database" cls loop     put "Enter desired username: " ..     get username     user (2).Username := username     cls     put "Desired password: " ..     get password     user (2).Password := password     user (2).Lines := lines     var temp : string := "temp2.txt"     var stream : int     open : stream, temp, put     put : stream, user (2).Lines     put : stream, user (2).Username     put : stream, user (2).Password     put : stream, user (2).Lines     close : stream     cls     put "-------------"     put "Username: " ..     put user (2).Username     put "Password: " ..     put user (2).Password     put "-------------"     put "Confirm? (Y/N)"     get confirm     if confirm = "y" then         exit     else         cls         File.Copy ("blank.txt", "temp.txt")         put "Data erased."     end if end loop cls put "Data successful entered into the database" cls var stream, stream2 : int open : stream, "temp.txt", get assert stream > 0 loop     exit when eof (stream)     get : stream, skip     get : stream, user(1).Lines     get : stream, user(1).Username     get : stream, user(1).Password     get : stream, user(1).Lines end loop close : stream open : stream, "temp2.txt", get assert stream > 0 loop     exit when eof (stream)     get : stream, skip     get : stream, user(2).Lines     get : stream, user(2).Username     get : stream, user(2).Password     get : stream, user(2).Lines end loop close : stream open : stream, "data.txt", put assert stream > 0     put : stream, user (1).Lines     put : stream, user (1).Username     put : stream, user (1).Password     put : stream, user (1).Lines     put : stream, user (2).Lines     put : stream, user (2).Username     put : stream, user (2).Password     put : stream, user (2).Lines close : stream

[Cervantes]

Just use one file, and use a for loop to get information for theentire array. Also, I would suggest using a flexible array here. Are you certain that there are 1400 users? Does that number ever change? If it does, you'll want to use a flexible array. Also, by using a flexible array, you could create a "Register" button, and when it's clicked, a new user is created. You could also make a "Delete Account" button.

[atrain]

Wow thanx so much for this tutorial...

had i read it before, it could have helped me quite a bit...
i only ended up with 3 arrays though....

[Drake]

How can I get one record to extend another record? For example, I'm making an RPG and I want to make a Monster record with the names of every monster in it. And I want each of those names to extend to another record so that I'm only using two records for the entire list. Is it possible to have this happen? I thought it would be something like this:

code:

var Stats :     record         Health : int         Mana : int         AttackMax : int         AttackMod : int         Defense : int     end record var Monster :     record         Druid : Stats         Dog : Stats         Rat : Stats         Snake : Stats         Zombie : Stats     end record

But that doesn't seem to work quite right. Especially when I try:

code:

Monster.Druid.Health := 25

Is it even possible to do this in as simple or a more simpler fashion?

[Cervantes]

Good question. It's possible. But let's look at what you've got first:
You've made a variable that contains fields for health and mana etc. Then, you've made a variable for several monsters, with fields whose typeSpec is a variable. This is not allowed; we want the typeSpec to be a type. So, change the first line from

code:

var Stats :

to

code:

type Stats :

Should work nicely now.

The other thing to think about is that you don't want to have to make variables for all the enemies in the game. A better way than what you've got there follows:

code:

var Monster : array 1 .. 10 of     record         Name : string         Health : int         Mana : int         AttackMax : int         AttackMod : int         Defense : int     end record

But, what would be even better is reading data in from a file, and using flexible arrays. I don't know how this RPG will work, but if it were to be a complex graphical RPG, I suggest making groups of monsters that are sorted by the map/level in which they appear and then by their x and y coordinates on the map. Then the individual monsters have their starting coordinates within the group.