Gambas/Maths

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The Cross Sum Program

This miniprogram calculates the cross sum of an integer. You need 2 textboxes and 1 commandbutton to get the program going.

Please beware of the signs / and \ . In this program the sign \ is used for a division without a remainder.

The Code

 PUBLIC SUB Button1_Click()

     DIM z AS Integer
     DIM crosssum AS Integer

     z = Val(TextBox1.Text)

     DO WHILE z <> 0 
       crosssum = crosssum + z MOD 10
       z= z \ 10 
     LOOP 

     TextBox2.Text = Str$(crosssum)
 END

Addy The Sum Program

This miniprogram calculates the sum of a row of integers. You need 1 textarea, 1 textbox and 1 commandbutton to get the program going. You can also add negative integers. Very helpful is the Split command and the String array String[]

The Code

PUBLIC SUB Button1_Click()
  DIM text AS String
  DIM summe AS Float
  DIM Elt AS String[]
  DIM Sb AS String

  text = textarea1.Text
  Elt = Split(text,Chr(10))

  FOR EACH Sb IN Elt
    summe = summe + Val(sb)
  NEXT

  textbox1.Text = summe
END

The Average Program

This miniprogram calculates the average of a row of integers. You need 1.textarea, 2 textboxes and 1 commandbutton to get the program going.

The Code

 PUBLIC SUB Button1_Click()
   DIM text AS String
   DIM summe AS Float
   DIM mw AS Float
   DIM varianz AS Float
   DIM sigma AS Float
   DIM Liste AS String[]
   DIM Einzelwert AS String

   text = textarea1.Text
   Liste = Split(text,Chr(10))

   FOR EACH Einzelwert IN Liste
      summe = summe + Val(Einzelwert)
   NEXT

   mw = summe / Liste.Length
   textbox1.Text = mw
   varianz = 0

   FOR EACH Einzelwert IN Liste
      varianz = varianz + ((Val(Einzelwert) - mw)^2)
      PRINT Einzelwert,mw,((Val(Einzelwert) - mw)^2)
      PRINT varianz
   NEXT

   varianz = varianz / (Liste.Length - 1)
   PRINT varianz
   sigma = Sqr(varianz)
   textbox2.Text = sigma
 END

The Median

The Median of a list of values lies between two equal parts of the list. 50% of the values ar greater or equal to the median. 50% are smaller or equal to the median. In contrary to the average the median is not influenced that much by extreme values.

If you want to program the median, you have to

• 1.sort your list of values
• 2.check if the list has an even or an odd number of values.
• 3.choose the right formula for the median.
  • for an odd number of values

xmedian = x[(n+1)/2]

• • for an even number of values

xmedian = 1/2*(x[n/2] + x[n/2+1])

example 1:

sorted list of values:

11
12
13
14
15    

The number of values is odd. n = 5

(n+1)/2 =  6/2 = 3 

xmedian = x[3] = 13

example 2.

sorted list of values:

11
12
13
14
15
16

The number of values is even , n = 6

n/2 =  6/2 = 3 
x[3] = 13
x[4] = 14
xmedian = 1/2*(13+14) = 13,5

You can take the list from above and copy it into the Gambas median program. Use the clipboard of your computer for that. Ctrl+C = Copy , Ctrl + V = Paste

example program

You need 2 textareas , 3 commandbuttons and 1 textbox, to get the program going:

' Gambas CLASS file
 PUBLIC liste AS String[]
 PUBLIC SUB Form_Open()
   ME.Text = "Computate the Median "
 END
 PUBLIC SUB Button1_Click()
 'sort
 Dim c AS Integer 
 Dim j AS Integer 
 Dim n AS Integer 
 Dim y AS Variant
 Dim liste AS String[]
 Dim element AS String 
 Dim txt AS String 
 Dim text AS String 
 text = Textarea1.Text
 liste = Split(text,Chr(10))
 y = 0
 n = liste.length
 REPEAT 
 c = 0
  FOR j = 0 TO n - 2
    'PRINT j,y,liste[0],ar[1],ar[2],ar[3],ar[4]
    IF Val(liste[j]) > Val(liste[j + 1]) THEN 
      y = Val(liste[j]) 
      liste[j] = liste[j + 1]
      liste[j + 1] = Str(y) 
      c = 1
    ENDIF 
  NEXT 
 UNTIL c = 0 
 FOR EACH element IN liste 
 txt = txt & Str(element) & Chr(10) 
 NEXT
 PRINT txt
 textarea2.Text = ""
 txt = Mid$(txt,1,-1)
 'the last CR has to be killed chr(10) 
 textarea2.Text = txt
 END
 PUBLIC SUB Button2_Click()
 'computate median, but sort first !! 
  Dim text AS String
  Dim median AS Float
  Dim liste AS String[]
  Dim posten AS String
  text = Textarea2.Text
  liste = Split(text,Chr(10))
  'count the length of your list and choose the right formula 
     IF liste.Length MOD 2 THEN 
   'PRINT liste.Length MOD 2 & " odd"
   'PRINT (liste.length + 1)/2
   'PRINT liste[(liste.length + 1)/2 - 1]
   median = Val(liste[(liste.length + 1)/2 - 1])
   'the array starts with the element 0 not with the element 1 !
   ELSE
   'PRINT liste.Length MOD 2 & " even"
   median = (Val(liste[liste.length/2 - 1]) + Val(liste[liste.length/2]))/2
   ENDIF 
  textbox1.Text = Str(median)
  END
  PUBLIC SUB Button3_Click()
  'list of values as an example 
  textarea1.Text = "114,3"
  textarea1.Text = textarea1.Text & Chr(10) & "135,7"
  textarea1.Text = textarea1.Text & Chr(10) & "104,8"
  textarea1.Text = textarea1.Text & Chr(10) & "118,5"
  textarea1.Text = textarea1.Text & Chr(10) & "125,7"
  textarea1.Text = textarea1.Text & Chr(10) & "121,4"
  textarea1.Text = textarea1.Text & Chr(10) & "122,4"
  textarea1.Text = textarea1.Text & Chr(10) & "96,8"
  textarea1.Text = textarea1.Text & Chr(10) & "118,9"
  textarea1.Text = textarea1.Text & Chr(10) & "120"
  textarea1.Text = textarea1.Text & Chr(10) & "112,2"
  textarea1.Text = textarea1.Text & Chr(10) & "127,9"
  textarea1.Text = textarea1.Text & Chr(10) & "122,8"
  textarea1.Text = textarea1.Text & Chr(10) & "128,9"
  textarea1.Text = textarea1.Text & Chr(10) & "120,3"
 'median = 120,3
 END