-----------------------------------

MysticAngel

Thu Mar 27, 2003 9:50 pm


LCD,GCM

-----------------------------------

i wanted to know whether there was any posts on GCD and LCM. i think i saw it. but i browsed thorugh a few pages of the post but coudnt find it. did anyone had any post about GCD and LCM ?  :?


-----------------------------------

Tony

Thu Mar 27, 2003 10:07 pm



-----------------------------------

no, there were not posts about them before... but I've found a nice site explaining how to program your own algorythms on them

http://mathforum.org/epigone/k12.ed.math/flenzhendfling/jh1j3tg3l0o76tencfqnesiuh8g1cato04@4ax.com


-----------------------------------

MysticAngel

Sat Mar 29, 2003 7:16 pm



-----------------------------------

i dont know much about function. i saw the tutorials. but it didnt give me any help. I sort of did how much i understood. i know that there are lot of errors . i cant figure out how to get rid of them.


function getpos () : int
var m : int
var n : int
put "Please enter a number"
get m
put ""
put "Please enter another number"
get n
end getpos

function GCD (n: int, m: int) : int
    var a, b, t : int
    getpos
    a:= m
    b := n
    loop
        t := a mod b
        exit when t = 0
        GCD := b
        a := b
        b := t
     end loop
end GCD
function LCM () : int
        getpos
        LCM (m, n) = (m + n) / gcd (m, n)
end LCM
function prime (n: int, m: int) : boolean
    GCD(m,n) = 1
end prime
getpos
put GCD
put LCM





-----------------------------------

Tony

Sat Mar 29, 2003 7:45 pm



-----------------------------------

function returns a value, so it must have result followed by a value. In your case, you want to use a procedure instead.

I'm sorry that tutorial didnt help you much... is there anything I can improve in it?


-----------------------------------

MysticAngel

Sun Mar 30, 2003 12:25 am



-----------------------------------

But i have to use functions. i cant use procedures yet. So can u check the code again and see if u tell me what is wrong
The tutorial can u a bit more example codes and a bit long ones like which use atleast 3 functions/ procedures (i guess) followed by what the program is doing - like what it the innput and the output stuff.  :!:  :)


-----------------------------------

yuethomas

Sun Mar 30, 2003 1:52 am



-----------------------------------

All functions must return values. So, what you can do is to return a dummy value (that doesn't actually accomplish anything), like:

function a (b : int) : int

...

    result 0
end a
What you attach after result is really up to you. Conventionally, it is put as 0 or 1 (to indicate success) and -1 (to indicate failure).


-----------------------------------

MysticAngel

Sun Mar 30, 2003 2:30 am



-----------------------------------

Dp u gave to sat like result = (something)?


-----------------------------------

azndragon

Sun Mar 30, 2003 9:49 am



-----------------------------------

Okay, let me use an example from my game:

function caps (word : string) : string                  %Converts a word into pure caps, so that the inputs can be more easily recognized.
    word2 := ""
    for i : 1 .. length (word)
        if ord (word (i .. i)) > 96 then
            if ord (word (i .. i)) < 123 then
                word2 := word2 + chr (ord (word (i)) - 32)
            else
                word2 := word2 + chr (ord (word (i)) + 0)
            end if
        else
            word2 := word2 + chr (ord (word (i)) + 0)
        end if
    end for
    result word2
end caps

First thing is the function name. That should be pretty simple. The variable in the brackets is the text that you input when you call the function. If you use the code:

caps(randomword)

The value stored in randomword will be sent to the function under the variable name of word. The middle section of the function can pretty much be ignored, since you can change it to whatever you want to do. However, notice that in the function, a new variable, called word2 is being created, based on the word variable. At the end of the function is "result word2" This is the final result of function. This will be set as a new variable if you call it sometime later. Ex.


var someword : string
var newword : string

put "Enter a word"
get someword

newword := caps (someword)

put newword

Lets say the user enters the word "Hello". The function will run through it's course, and word2 will now be "HELLO". The result is given, and the final output of the program is "HELLO". Hope this helps.


-----------------------------------

MysticAngel

Mon Mar 31, 2003 4:31 pm



-----------------------------------

k sort og know what functions are and how they work and stuff. but i am not sure whether my code is ok or not. plz check it, cuz there are  a few errors and i cant figure them out. plz tell me what are are the mistakes/ solutions


-----------------------------------

MysticAngel

Mon Mar 31, 2003 9:49 pm



-----------------------------------


function getPositiveInteger : int
    var n : int
    loop
        get n
        exit when n > 0
        put " A positive value please :"
    end loop
    result n
end getPositiveInteger
%------------------------------------------------------
function GreatestCommonDivisor (n : int) : int
    var greatest,t, a , b,m : int
    m:= getPositiveInteger
        a := m
        b := n
        loop    
            t := a mod b
            exit when t < 1            
            a:= b
            b:= t
            result b
        end loop
end GreatestCommonDivisor
%------------------------------------------------------    
function LeastCommonMultiple (m,n : int) :int
    var lcm : int
    lcm := (m*n) / GreatestCommonDivisor(m,n)
    result lcm
end LeastCommonMultiple
%-----------------------------------------------------
function relativelyprime(m,n : int) : boolean
    if GreatestCommonDivisor = 1 then
        relativelyprime = true
    else
        relativelyprime = false
    end if
    result relativelyprime (m,n)
end relativelyprime
    
%-----------------------------------------------------------
var num1, num2,a1, b1 : int
var c1 : boolean
loop
put "Please enter a number"
    num1:= getPositiveInteger (n)
put "Please enter another number"
    num2 := getPositiveInteger(m)
put "GCD = "
    a1:= GreatestCommonDivisor 
    put a1
put "LCM = "
    b1 = LeastCommonMultiple (m,n)
    put b1
 put "Relatively prime"
    c1 := relativelyprime
    put c1
end loop




-----------------------------------

Tony

Mon Mar 31, 2003 10:47 pm



-----------------------------------

this doesnt seem to work yet :?


-----------------------------------

MysticAngel

Mon Mar 31, 2003 11:16 pm



-----------------------------------

I was supposed to attached the code to the previous reply. i forgot to. :oops: 
k sort og know what functions are and how they work and stuff. but i am not sure whether my code is ok or not. plz check it, cuz there are a few errors and i cant figure them out. plz tell me what are are the mistakes/ solutions

[/code]
function getPositiveInteger : int 
    var n : int 
    loop 
        get n 
        exit when n > 0 
        put " A positive value please :" 
    end loop 
    result n 
end getPositiveInteger 
%------------------------------------------------------ 
function GreatestCommonDivisor (n : int) : int 
    var greatest,t, a , b,m : int 
    m:= getPositiveInteger 
        a := m 
        b := n 
        loop    
            t := a mod b 
            exit when t < 1            
            a:= b 
            b:= t 
            result b 
        end loop 
end GreatestCommonDivisor 
%------------------------------------------------------    
function LeastCommonMultiple (m,n : int) :int 
    var lcm : int 
    lcm := (m*n) / GreatestCommonDivisor(m,n) 
    result lcm 
end LeastCommonMultiple 
%----------------------------------------------------- 
function relativelyprime(m,n : int) : boolean 
    if GreatestCommonDivisor = 1 then 
        relativelyprime = true 
    else 
        relativelyprime = false 
    end if 
    result relativelyprime (m,n) 
end relativelyprime 
    
%----------------------------------------------------------- 
var num1, num2,a1, b1 : int 
var c1 : boolean 
loop 
put "Please enter a number" 
    num1:= getPositiveInteger (n) 
put "Please enter another number" 
    num2 := getPositiveInteger(m) 
put "GCD = " 
    a1:= GreatestCommonDivisor 
    put a1 
put "LCM = " 
    b1 = LeastCommonMultiple (m,n) 
    put b1 
put "Relatively prime" 
    c1 := relativelyprime 
    put c1 
end loop


-----------------------------------

Prince

Tue Apr 01, 2003 11:38 am



-----------------------------------

whoa, u got a shit load of errors there... ive got the same program at home (i think... i hope  :?)... r u in the gr 11 comp sci class?


-----------------------------------

Dan

Tue Apr 01, 2003 4:41 pm



-----------------------------------

The function GreatestCommonDivisor only takes one number  but it is beiing called with 2.  also you some times calling it with no numbers wich  dose not wrok.

also in turing  you use := not = when  asing a vlaue you messed that up a few  times  :? 

then you send a vlaue, n to the a fuction that has no vlaue and you do not input the users repose to put in a number.


-----------------------------------

MysticAngel

Tue Apr 01, 2003 6:13 pm



-----------------------------------

yes i am in grade 11. neways i cahnged some stuff and it works now but theere are some problems in the output. k when u run the code. it works correctly, but after u enter the two numbers, u have to enter another number then u would get the GCD and then again u would have to enter another number even when it is not asking for then you would get the other results... :? 


function getPositiveInteger : int
    var n : int
    loop
        get n
        exit when n > 0
    end loop
    result n
end getPositiveInteger
%------------------------------------------------
function GreatestCommonDivisor (m, n : int) : int
    var greatest, t, a, b, c : int
    c := getPositiveInteger
    a := c
    b := n
    loop
        t := a mod b
        exit when t < 1
        a := b
        b := t
        result b
    end loop
end GreatestCommonDivisor
%------------------------------------------------
function LeastCommonMultiple (m, n : int) : int
    var lcm : int
    lcm := (m * n) div GreatestCommonDivisor (m, n)
    result lcm
end LeastCommonMultiple
%------------------------------------------------
function relativelyprime (m, n : int) : boolean
    var bool : boolean := false
    if GreatestCommonDivisor (m, n) = 1 then
        bool := true
    end if
    result bool
end relativelyprime

%-----------------------------------------------------------
var num1, num2, a1, b1 : int
var c1 : boolean
loop
    put "Please enter a number"
    num1 := getPositiveInteger
    put "Please enter another number"
    num2 := getPositiveInteger
    a1 := GreatestCommonDivisor (num1, num2)
    put "GCD = ", a1
    b1 := LeastCommonMultiple (num1, num2)
    put "LCM = ", b1
    c1 := relativelyprime (num1, num2)
    put "Relatively prime", c1
end loop



-----------------------------------

yuethomas

Tue Apr 01, 2003 7:18 pm



-----------------------------------


...
    c := getPositiveInteger
...


This line prompts you to enter another number for C. As I am not familiar with the algorithm for calculating the GCM of two numbers, I have no idea what it's for.

Update:

After analyzing the algorithm, I think it's perfectly safe to change
    var greatest, t, a, b, c : int
    c := getPositiveInteger
    a := c

into
    var t, a, b : int
    a := m



-----------------------------------

MysticAngel

Wed Apr 02, 2003 6:06 pm



-----------------------------------

i dont know why this isnt working ????

function getPositiveInteger : int
    var n : int
    loop
        get n
        exit when n > 0
        put "Positive interger please  " ..
    end loop
    result n
end getPositiveInteger
%--------------------------------------------
function Factorial(n: int): real
    var count, count1 : int
    loop
        count := count + 1
        count1 := count1 * count
        exit when count = n
        end loop
    result count1
end Factorial
%-----------------------------------------
function Permutation (n, r : int) : real   
    var p : int
    p := Factorial(n) div (n - r)
    result p
end Permutation
%----------------------------------------
function Combination (n, r : int) : real
    var c : int
    c := Factorial(n)  div r*(n-r)
    result c
end Combination
%------------------*Main Program-------------------------
var num1, num2, a, b : int
put "Please enter a positive number"
num1 := getPositiveInteger
put "Please enter another positve number"
num2 := getPositiveInteger
if num1 >= num2 then
    a := Permutation(num1,num2)
    put a
    b :=Combination (num1,num2) 
    put b
end if




-----------------------------------

Tony

Wed Apr 02, 2003 6:19 pm



-----------------------------------

thats because your functions return real values, but you try to assign them to integer varaibles.

declear a,b as real and it should work


-----------------------------------

MysticAngel

Wed Apr 02, 2003 8:20 pm



-----------------------------------

is this correct. like this is n!. if u input 5 the answer shuld be (5! = 1*2*3*4*5) = 120


[/code]
function Factorial(n: int): real
    var count,e : int
    count := 1
    loop
        count := count + 1
        e := 1 * count
        exit when count = n
        end loop
    result n
end Factorial


-----------------------------------

Prince

Wed Apr 02, 2003 8:35 pm



-----------------------------------

try splitting the factorial function so ur finding the factorial of num1, num2 and num1 - num2... finding the permutations and combinations should b easier then


-----------------------------------

MysticAngel

Wed Apr 02, 2003 8:43 pm



-----------------------------------

huh ?????  :?


-----------------------------------

MysticAngel

Wed Apr 02, 2003 9:20 pm



-----------------------------------

I dont understand what u said. how do i do that


-----------------------------------

Prince

Wed Apr 02, 2003 9:24 pm



-----------------------------------

like this


function nFactorial (n : int) : real
    var N : real := 1
    for j : 1 .. n
        N := N * j
    end for
    result N
end nFactorial


thats for num1


function rFactorial (r : int) : real
    var R : real := 1
    for j : 1 .. r
        R := R * j
    end for
    result R
end rFactorial


thats num2


function nrFactorial (var n, r : int) : real
    var NR : real := 1
    for j : 1 .. n - r
        NR := NR * j
    end for
    result NR
end nrFactorial


and that one is num1 - num2... it may seem confusing (ok it really is) but its really not that hard (especially since i did this last year  :D)

MOD Edit: thx for the help +10Bits - Tony


-----------------------------------

MysticAngel

Wed Apr 02, 2003 9:30 pm



-----------------------------------

So when i call it somewhere i would call nrFactorial rite?


-----------------------------------

Prince

Wed Apr 02, 2003 9:45 pm



-----------------------------------

thats rite


-----------------------------------

yuethomas

Wed Apr 02, 2003 9:56 pm



-----------------------------------

Uh, a factorial can only result in an integer. No sense declaring it as a REAL function.


-----------------------------------

Prince

Wed Apr 02, 2003 10:14 pm



-----------------------------------

test any one of those functions with a value over 10 and u'll see y it has to b REAL... did u do it?? ok then...


-----------------------------------

Tony

Wed Apr 02, 2003 10:43 pm



-----------------------------------

damn low level turing  :evil: C++'s int variable is much larger is size  :D


-----------------------------------

MysticAngel

Sat Apr 05, 2003 5:57 pm



-----------------------------------

in a number theory, wat does the sum of the proper factors of a number mean. i mean how would you frame it.


-----------------------------------

yuethomas

Sun Apr 06, 2003 1:04 am



-----------------------------------

Proper factors of a number is the factors of that number except 1 and the number itself. For example, the proper factors of 30 are 2, 3, 5, 6, 10, and 15.

So the sum of the proper factors of 30 would be 2+3+5+6+10+15=31.


-----------------------------------

MysticAngel

Sun Apr 06, 2003 10:13 am



-----------------------------------

l how would u frame the code ?


-----------------------------------

yuethomas

Sun Apr 06, 2003 11:27 am



-----------------------------------

Oh sorry, I misunderstood.

I don't know of any algorithms, so I'll use a dumb one here... 

 % checking proper factors of a

var a : int := 30

var sum : int := 0

% an optimisation note: when a is odd
% the largest factor cannot exceed a/3;
% when a is even it cannot exceed a/2.

if floor(a/2) = a/2 then % checks for parity

    for b : 2 .. floor (a/2)

    % even though a/2 is an integer,
    % I doubt a/2 will return a variable
    % of type integer... so just wrap it
    % in a function that returns a integer.

        if floor (a/b) = a/b then sum += b

    end for

else % a is odd

    for b : 3 .. ceil (a/3)

    % now a isn't necessarily divisible by
    % 3, so take the larger value here
    % just to be safe

        if floor (a/b) = a/b then sum += b

    end for

end if

put "SUM OF PROPER FACTORS OF ", a, " IS ", b


-----------------------------------

Prince

Mon Apr 07, 2003 10:02 am



-----------------------------------


function properFactors (n : int) : int
    var x, y, temp : int := 0
    for decreasing i : n .. 1 by 1
        x := n mod i
        if x = 0 then
            y := n div i
            if y not= n then
                temp := temp + y
            end if
        end if
    end for
    result temp
end properFactors


now doesnt that seem a whole lot simpler... it works too :D


-----------------------------------

Prince

Mon Apr 07, 2003 10:04 am



-----------------------------------

btw, yuethomas, proper factors do include 1


-----------------------------------

yuethomas

Mon Apr 07, 2003 4:35 pm



-----------------------------------

My mistake.


-----------------------------------

MysticAngel

Wed Apr 09, 2003 9:19 pm



-----------------------------------

Can u plz check my code. It is supposed to give the reverse of a number.
eg. 72--27



function reverse (n:int) : int
    var digits,sum,r : int
    var count : int := 0
    loop
        digits := n mod 10
        r := n div 10
        count := count + 1        
        exit when count >= 0
    end loop    
    result digits
end reverse


-----------------------------------

Asok

Wed Apr 09, 2003 9:27 pm



-----------------------------------

I believe that was allready posted for reversing numbers, actually I guarantee it. Search the forums.


-----------------------------------

MysticAngel

Wed Apr 09, 2003 9:35 pm



-----------------------------------

but u are using instr... which i dont want to use, there are errors there anyways..... i know how to do it without the function. but when i use the function i get a bit confused like what to ouput. my code gives out i think just the first reverse number. can u plz check it  :( 



function reverse (n:int) : int 
    var digits,sum,r : int 
    var count : int := 0 
    loop 
        digits := n mod 10 
        r := n div 10 
        count := count + 1        
        exit when count >= 0 
    end loop    
    result digits 
end reverse


-----------------------------------

yuethomas

Wed Apr 09, 2003 9:46 pm



-----------------------------------

function reverse (n:int) : int 
    var digits : int 
    var count : int := 0 
    var r: int := n
    loop 
        digits := digits * 10 + r mod 10
        r := r div 10
        exit when r = 0        
    end loop
    result digits
end reverse

Edit: (thank you Tony)


-----------------------------------

Tony

Wed Apr 09, 2003 9:49 pm



-----------------------------------

well its all wrong.

it will result in n mod 10 which is the remainder of n after dividing by 10. Since your exit statment will get you out of loop right away. I dont even understand what you're trying to do :?

first of all... to get the number of digits, you keep on dividing by multiples of 10 until your result is