Procedure Vs. Funtion

[AzureFire]

I saw a post that said procedures aren't reliable, and not to use them. So I was wondering, is function the same thing? And if it is, is there a difference?

Thanks

[Cervantes]

Procedures are fine. Processes are not.

[masterfenix]

A procedure is just a normal peice of code.


a function is usually when you want to do a calculation and get a result.

functiosn have to result 1 thing. and it can only result one.

while in a procedure you can caluclate stuff, and send it out to variables.

[Delos]

masterfenix wrote:

A procedure is just a normal peice of code.


a function is usually when you want to do a calculation and get a result.

functiosn have to result 1 thing. and it can only result one.

while in a procedure you can caluclate stuff, and send it out to variables.

Hmm...this sounds oddly off-course. While you may have the right idea, it's not quite - uh - precise.

Procedures are compartmentalized pieces of code, which theoretically have no idea that an outside world exists. To them, they see something coming in (their parameters), do stuff with them (perhaps incorportating some of their own local vars), then send stuff out again into the great, big oblivion.
Functions are very similar, and effectively produce a single result. I say effectively, since if used in conjunction with records, they can produce quite a few results packaged as one.

AzureFire is probably referring to processes, as Cervantes mentioned, though he may be talking about the wtd-popularized concept that functions are inherently more flexible than procedures in many situations. The most common situation where people use procedures instead of the more efficient functions would be in the initialization of a record type. I.e.:

Turing:

type quickType :     record         name : string         value : int     end record procedure p_initQT (var inQT : quickType, inName : string, inValue : int)     inQT.name := inName     inQT.value := inValue end p_initQT function f_initQT (inName : string, inValue : int) : quickType     var tempQT : quickType     tempQT.name := inName     tempQT.value := inValue     result tempQT end f_initQT var qt1, qt2 : quickType % So, using: p_initQT (qt1, "QT1", 1) % Instead of: qt2 := f_initQT ("QT2", 2)

[MysticVegeta]

Delos wrote:

Procedures are compartmentalized pieces of code, which theoretically have no idea that an outside world exists

uh dont they check the "outside world" if they have some vars in them that are not local to check and see if they are global?

[Cervantes]

Nice stuff Delos. Every post is a tutorial.

Delos wrote:

Functions are very similar, and effectively produce a single result. I say effectively, since if used in conjunction with records, they can produce quite a few results packaged as one.

You can also return an array of values. The key thing to note, however, is that you cannot return a dynamic amount/type of data: You can't return an array of compile-time-unknown length. That sucks, hugely.

MysticVegeta: Notice how he said "theoretically". You can have procedures access the outside world via global variables, but it is bad coding practice. The procedure should be able to perform its function in any program, given its input parameters. Moving the procedure from one program to another (and hence changing the global variables present) destroys this philosophy.

[Clayton]

MysticVegeta wrote:

Delos wrote:

Procedures are compartmentalized pieces of code, which theoretically have no idea that an outside world exists

uh dont they check the "outside world" if they have some vars in them that are not local to check and see if they are global?

procs do in fact check to see if vars inside of procs are global. this is an easy way of using variables that u dont want to change from one proc (or function) to the next without using parameters, and you can send them off to the next procedure too.

[Clayton]

code:

%sees if a number is greater than ten, or less than ten %global variable %this is just an example, this could be done easier and better with parameters but it is an example var number:int:=0 %procedures proc greaterLess      if number>=10 then           Draw.Cls           put "Your number is greater than 10"      else           put "Your number is less than 10"      end if end greaterLess %Main Line put "Please enter a number" get number greaterLess

[AzureFire]

SuperFreak82 wrote:

code:

%sees if a number is greater than ten, or less than ten %global variable %this is just an example, this could be done easier and better with parameters but it is an example var number:int:=0 %procedures proc greaterLess      if number>=10 then           Draw.Cls           put "Your number is greater than 10"      else           put "Your number is less than 10"      end if end greaterLess %Main Line put "Please enter a number" get number greaterLess

Annnndddd your point is?


Anyway, thanks for the answers. And yes i was confused by procedures and processes. Must have misread it.

[Clayton]

AzureFire wrote:

SuperFreak82 wrote:

code:

%sees if a number is greater than ten, or less than ten %global variable %this is just an example, this could be done easier and better with parameters but it is an example var number:int:=0 %procedures proc greaterLess      if number>=10 then           Draw.Cls           put "Your number is greater than 10"      else           put "Your number is less than 10"      end if end greaterLess %Main Line put "Please enter a number" get number greaterLess

Annnndddd your point is?

i was just showing how procs search for vars outside of the proc itself
Anyway, thanks for the answers. And yes i was confused by procedures and processes. Must have misread it.