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m0rb1d · Nov 30th, 2006, 8:05 AM

Continuing along with this tutorial I have been working on, it explains subs and functions. From the examples given, it looks to me, as if they do the same things.

I have been working on a text based RPG. I figured, making it will help me in retaining what I have learned so far. It came to a point where I could use the first function/sub, but, it is slightly confusing as to the manner in which you use them.

According to the tutorial, it should go something like:

(Toggle Plain Text)

PRINT "BLahblah goes here. Big scary monster trying to eat your head."
PRINT
PRINT "1. Attack the monster."
PRINT "2. Run away screaming for your mother."
PRINT
INPUT "What will you do? 1 or 2.", choice%
IF choice% = 1 THEN
     monsterStats   ' this is the name given to the function
     PRINT "You attack the monster with your weapon."
IF attack% >= mobEva% THEN 
     damage% = attack% - mobEva% + weapBonus%
     mobHP% = mobHP% - damage%
END IF
PRINT "You hit the monster for "; damage%; "damage."
IF mobHP% = 0 THEN
     PRINT "You have killed the monster."
     exp% = mobExp% + exp%

Well, you get the idea. After typing this out, I have realised, there is a couple more things I could have used funtions for. But, for the sake of keeping my sanity, I will revert to my original question. Would SUB have worked just as easily as FUNCTION?

And yet again, an epiphany. Putting 2 and 2 to together, I'll ration, SUB = SUB FUNCTION? Following this rational, SUB should be used inside a FUNCTION? I may have successfully confused someone people, including myself, so I will include the tutorial chapter that I am reading. It gave no example of a SUB being used inside a FUNCTION.

Biggest problem I'm having I suppose, is that what I assume should work, does not.

Arevos · Nov 30th, 2006, 8:14 AM

IIRC, in QBASIC, a function returns a value as output, whereas a subroutine does not.

m0rb1d · Nov 30th, 2006, 8:34 AM

After rereading that tutorial, it seems SUB's DO something, and functions return a value.

So, I suppose the actual question I'm looking for an answer to is...

Im wanting to generate 3 values, and assign them to variables. This will need to be done repeatedly throughout the program.

Following the SUB doing something, and functions returning a number, it would seem that it's possible to achieve this by using FUNCTION. But, can FUNCTION give the value of 3 things at once?

Such as, the monsters HP, the monsters EXP value, and the monsters Gold value? Or, would I have to use 3 seperate functions?

Arevos · Nov 30th, 2006, 8:53 AM

You could DIM an array and return that. I believe there's also a way to DIM a data structure, similar to structs in C, but it's been years since I touched QBASIC, I'm afraid. To use an analogy, QBASIC akin to a flint knife in a world where iron has become commonplace. Tasks which are trivial in other languages are sometimes difficult to do within QBASIC's limited featureset.

DaWei · Nov 30th, 2006, 9:48 AM

At this stage, I believe you'd be fine using separate functions. You might not always want to do all three things at once, anyway. Pseudo-code example:

(Toggle Plain Text)

   monsterHP = getHP (possibleArg)
   monsterEXP = getEXP ()
   monsterGOLD - getGOLD ()

This would presume that the get functions were something other than a trivial assignment. "possibleArg" might indicate some multiplier or other control on how much of an attribute you want to get.

m0rb1d · Nov 30th, 2006, 10:13 AM

So, if I understand this correctly, the functions in your example would be:

(Toggle Plain Text)

FUNCTION getHP
RANDOMIZE TIMER
getHP = charHP% - (RND * 10) + 1
END FUNCTION

This would ensure that the monsters HP is not always the same, and that they would scale appropriately as the character leveled up.

Was this what you were expressing?

DaWei · Nov 30th, 2006, 10:48 AM

Something like that. Anything you need to do repetetively, that isn't trivial, should be modularized (become a function or sub). With a little thought, you will see that such things can be very useful. The best and most utilitarian can become building blocks that you use to assemble other programs from. Get 'em off the shelf and bolt 'em on, so to speak.

m0rb1d · Dec 2nd, 2006, 5:13 AM

For the life of me, I cannot get FUNCTIONS, or SUBS to work. I am using them as follows:

(Toggle Plain Text)

PRINT "blah blah"
PRINT "more blah blah"
PRINT "even more blah blah"
getClass

I've tried about a million times, and I always seem to get an error. In this example, it will print what I have inside the SUB getClass, but it doesn't seem to recognize the INPUT command. It just prints it instead, and continues on with the rest of the code.

Same thing is happening with FUNCTIONS, only, I get mismatch errors, or duplicate definition errors. I thought for a while, I was just using it wrong, but, I am not sure anymore.

Any idea what I am doing wrong?

Arevos · Dec 2nd, 2006, 5:31 AM

You probably have to give the function some arguments. See here

m0rb1d · Dec 2nd, 2006, 6:44 AM

Hm, seems the more I learn, the more confusing it gets, and the more questions I end up having. Such as,

Can you use a variable?

Combat -

(Toggle Plain Text)

180
PRINT "What would you like to do?: "
PRINT
PRINT "1. Attack "
PRINT "2. Run Away"
PRINT
INPUT "Your choice?", choice%
IF choice% = 1 THEN
     CALL combat(hit%)
     CALL defense(def%)
     ELSE GOTO 190
END IF
IF hit% > def% THEN
     CALL damage(dam%)
ELSE PRINT "You missed."
END IF
mobHP% = mobHP% - dam%
IF mobHP% <= 0 THEN
     GOTO 185
ELSE GOTO END

SUB combat(hit%)
RANDOMIZE TIMER
hit% = INT(RND * 20) + 1
END SUB

SUB defense(def%)
def% = eva% + armBonus%
END SUB

SUB damage(dam%)
dam% = hit% - def%
END SUB

Nov 30th, 2006, 9:48 AM	#5
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	At this stage, I believe you'd be fine using separate functions. You might not always want to do all three things at once, anyway. Pseudo-code example: (Toggle Plain Text) monsterHP = getHP (possibleArg) monsterEXP = getEXP () monsterGOLD - getGOLD () monsterHP = getHP (possibleArg) monsterEXP = getEXP () monsterGOLD - getGOLD () This would presume that the get functions were something other than a trivial assignment. "possibleArg" might indicate some multiplier or other control on how much of an attribute you want to get. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Nov 30th, 2006, 10:13 AM	#6
m0rb1d Newbie Join Date: Nov 2006 Posts: 19 Rep Power: 0	So, if I understand this correctly, the functions in your example would be: (Toggle Plain Text) FUNCTION getHP RANDOMIZE TIMER getHP = charHP% - (RND * 10) + 1 END FUNCTION FUNCTION getHP RANDOMIZE TIMER getHP = charHP% - (RND * 10) + 1 END FUNCTION This would ensure that the monsters HP is not always the same, and that they would scale appropriately as the character leveled up. Was this what you were expressing?

Nov 30th, 2006, 10:48 AM	#7
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Something like that. Anything you need to do repetetively, that isn't trivial, should be modularized (become a function or sub). With a little thought, you will see that such things can be very useful. The best and most utilitarian can become building blocks that you use to assemble other programs from. Get 'em off the shelf and bolt 'em on, so to speak. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Dec 2nd, 2006, 5:13 AM	#8
m0rb1d Newbie Join Date: Nov 2006 Posts: 19 Rep Power: 0	For the life of me, I cannot get FUNCTIONS, or SUBS to work. I am using them as follows: (Toggle Plain Text) PRINT "blah blah" PRINT "more blah blah" PRINT "even more blah blah" getClass PRINT "blah blah" PRINT "more blah blah" PRINT "even more blah blah" getClass I've tried about a million times, and I always seem to get an error. In this example, it will print what I have inside the SUB getClass, but it doesn't seem to recognize the INPUT command. It just prints it instead, and continues on with the rest of the code. Same thing is happening with FUNCTIONS, only, I get mismatch errors, or duplicate definition errors. I thought for a while, I was just using it wrong, but, I am not sure anymore. Any idea what I am doing wrong?

Dec 2nd, 2006, 6:44 AM	#10
m0rb1d Newbie Join Date: Nov 2006 Posts: 19 Rep Power: 0	Hm, seems the more I learn, the more confusing it gets, and the more questions I end up having. Such as, Can you use a variable? Combat - (Toggle Plain Text) 180 PRINT "What would you like to do?: " PRINT PRINT "1. Attack " PRINT "2. Run Away" PRINT INPUT "Your choice?", choice% IF choice% = 1 THEN CALL combat(hit%) CALL defense(def%) ELSE GOTO 190 END IF IF hit% > def% THEN CALL damage(dam%) ELSE PRINT "You missed." END IF mobHP% = mobHP% - dam% IF mobHP% <= 0 THEN GOTO 185 ELSE GOTO END SUB combat(hit%) RANDOMIZE TIMER hit% = INT(RND * 20) + 1 END SUB SUB defense(def%) def% = eva% + armBonus% END SUB SUB damage(dam%) dam% = hit% - def% END SUB 180 PRINT "What would you like to do?: " PRINT PRINT "1. Attack " PRINT "2. Run Away" PRINT INPUT "Your choice?", choice% IF choice% = 1 THEN CALL combat(hit%) CALL defense(def%) ELSE GOTO 190 END IF IF hit% > def% THEN CALL damage(dam%) ELSE PRINT "You missed." END IF mobHP% = mobHP% - dam% IF mobHP% <= 0 THEN GOTO 185 ELSE GOTO END SUB combat(hit%) RANDOMIZE TIMER hit% = INT(RND * 20) + 1 END SUB SUB defense(def%) def% = eva% + armBonus% END SUB SUB damage(dam%) dam% = hit% - def% END SUB

Nov 30th, 2006, 8:14 AM	#2
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 5	IIRC, in QBASIC, a function returns a value as output, whereas a subroutine does not.

Nov 30th, 2006, 8:34 AM	#3
m0rb1d Newbie Join Date: Nov 2006 Posts: 19 Rep Power: 0	After rereading that tutorial, it seems SUB's DO something, and functions return a value. So, I suppose the actual question I'm looking for an answer to is... Im wanting to generate 3 values, and assign them to variables. This will need to be done repeatedly throughout the program. Following the SUB doing something, and functions returning a number, it would seem that it's possible to achieve this by using FUNCTION. But, can FUNCTION give the value of 3 things at once? Such as, the monsters HP, the monsters EXP value, and the monsters Gold value? Or, would I have to use 3 seperate functions?

Nov 30th, 2006, 8:53 AM	#4
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 5	You could DIM an array and return that. I believe there's also a way to DIM a data structure, similar to structs in C, but it's been years since I touched QBASIC, I'm afraid. To use an analogy, QBASIC akin to a flint knife in a world where iron has become commonplace. Tasks which are trivial in other languages are sometimes difficult to do within QBASIC's limited featureset.

Dec 2nd, 2006, 5:31 AM	#9
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 5	You probably have to give the function some arguments. See here

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Programming Forums > Application Development > Other Programming Languages

QBasic - The purpose of FUNCTION and SUB