I'm trying to list all numbers with 3 digits where the individual digits sum to a given number.
So far I can return a list of all numbers using this Visual Basic code:
target = 17
i = 1
j = 1
k = 1
Do While i < 10
Do While j < 10
Do While k < 10
r = i + j + k
If r = target Then
If i <> j And j <> k And k <> i Then
lsNumbers.Add(i & j & k )
End If
End If
k += 1
Loop
If k = 10 Then k = 1
j += 1
Loop
If j = 10 Then j = 1
i += 1
Loop
But I want only unique, non repeating combinations.
For example for the target number 17:
179, 197, 269, 278, 287...
I want to be able to test the current number before I add it to the list, to check if it is a combination of a number already in the list - so 197 would fail because of 179, and 287 would fail because of 278
Observations
Just curious, is excluding the 0 digit on purpose?
To iterate through the possible digits, a well suited instruction pair is FOR NEXT. Definitely simpler than the DO WHILE that you used.
Loop
If k = 10 Then k = 1
Loop
If j = 10 Then j = 1
Upon loop completion, the iterator is sure to contain 10. The IF is redundant.
Solution
In order to check if a number, that obeys the condition, is unique in the sense that it is not composed of the same 3 digits as an already validated number, you could consult a 3-D array. If the new number corresponds to a non-zero element in this array, it means that the new number would be using the same digits as an earlier number. That's reason to reject it.
Next code runs in QBasic. You'll have no trouble rewriting it for Visual BASIC.
DIM r%(1 TO 9, 1 TO 9, 1 TO 9)
FOR i% = 1 TO 9
FOR j% = 1 TO 9
FOR k% = 1 TO 9
r%(i%, j%, k%) = 0
NEXT
NEXT
NEXT
target% = 17
FOR i% = 1 TO 9
FOR j% = 1 TO 9
FOR k% = 1 TO 9
IF i% + j% + k% = target% THEN
IF r%(i%, j%, k%) = 0 THEN
PRINT i% * 100 + j% * 10 + k%; " ";
r%(i%, j%, k%) = 1 ' Could do without this one because of the ascending order
r%(i%, k%, j%) = 1
r%(j%, i%, k%) = 1
r%(j%, k%, i%) = 1
r%(k%, i%, j%) = 1
r%(k%, j%, i%) = 1
END IF
END IF
NEXT
NEXT
NEXT
This is my output of valid numbers:
179 188 269 278 359 368 377 449 458 467 557 566
Related
I am looping through a card number finding all the odd numbers and multiplying them by the card digits. Its kind of hard to explain. I am having trouble multiplying the odd number and the card number. Here's an example my teacher gave me. You multiply card number 1 and and odd number 1 and so forth. I am not getting any errors, it just kind of freezes.
Sums
Card #: 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
Multiples 1 2 3 4 5 6 7 8
Evens: 2 4 6 8 0 2 4 6 32 =Sum 1
Odds: 1 6 15 28 45 6 21 40 162 =Sum 2
Sum 3: 194
194 =Sum 3
Step 4: =1+9+4 = 14
= 1 + 4 = 5 = check digit
Public Class Payment
Private Sub OK_Click(sender As Object, e As EventArgs) Handles OK.Click
Dim Sum1 = 0
Dim Sum2 = 0
Dim Sum3 = 0
Dim ready As Boolean
Dim ccnumb = CardNumber.Text
Format(CardNumber.Text, "################")
Dim exp = Mid(ExpDate.Text, 1, 3)
Dim checkdigit = 0
If FullName.TextLength = 0 Or cardtype.Text.Length = 0 And ccnumb.Length <= 16 Or exp.Length = 2 Then
MessageBox.Show("Please enter all credit card information before proceeding.")
ready = False
Else ready = True
End If
If ready = True Then
For Each num As Char In ccnumb
If CInt(CStr(num)) Mod 2 <> 0 Then
Sum1 += CInt(CStr(num)) * CInt(CStr(num)) Mod 2 <> 0
Else
Sum2 += CInt(CStr(num))
End If
Next
Sum3 = Sum1 + Sum2
Do While Sum3 > 10
For j = 0 To Sum3.ToString.Length - 1
For k = 1 To Sum3.ToString.Length - 1
Sum3 = j + k
Next
Next
Loop
Do While exp.Length > 1
checkdigit = Mid(ExpDate.Text, 1, 1) + Mid(ExpDate.Text, 1, 2)
Loop
If Sum3 = checkdigit Then
MessageBox.Show("Congratulations! Your payment was successful.")
CustInv.Show()
Else MessageBox.Show("The checkdigit," & Space(1) & Sum3 & Space(1) & "does not match the month code," & Space(1) & checkdigit & "." & Space(1) & "Please reenter your card information.")
End If
End If
End Sub
"it kind of freezes" is lay speak for "my code enters an infinite loop".
This looks suspicious:
Do While Sum3 > 10
For j = 0 To Sum3.ToString.Length - 1
For k = 1 To Sum3.ToString.Length - 1
Sum3 = j + k
Next
Next
Loop
To enter the loop, Sum3 must be greater than 10. For the loop to exit, Sum3 must not be greater than 10, but your code only increments Sum3, so Sum3 can only stay greater than 10.
This means that once entered, this loop is infinite.
If changing outer loop to inside loop doesn't help you
Try this
Do While Sum3 > 10 and j < sum3 ' adding j < sum3 might stop the loop
For j = 0 To Sum3.ToString.Length - 1
For k = 1 To Sum3.ToString.Length - 1
Sum3 = j + k
Next
Next
Loop
I'm new to Excel VBA and i'm trying to make a loop that sums X = X + 1 but when the loop ends it continues with the last X and doesn't starts again.
This is what I have:
For I = 1 To 3
J = 2
For K = 1 To J * 2 Step 1
Debug.Print K
Next K
Next I
This is what i get: 1 2 3 4 1 2 3 4 1 2 3 4 .
What i would like to get is: 1 2 3 4 5 6 7 8 9 10 11 12 .
Thanks for the help provided. I thought this would solve my problem but it's a bit more complicated. I need this because i'm adding coordinates in X, Y, Z format with this code:
For I = 1 To 6
X = 0
J = 10
RobApp.Project.Structure.Nodes.Create X = X + 1, 0, 0, J * (I - 1)
RobApp.Project.Structure.Nodes.Create X = X + 1, Range("N34") * 0.15, 0, J *
(I - 1)
Next I
"X = X+1" is the node number. I want it to be sequencial, 1,2,3,4 and so on while J is increasing in the Z coordinate. For example for the first line of code:
Node 1 = 0,0,0
Node 2 = 0,0,10
Node 3 = 0,0,20
and so on!
Or rather, use the extra variable X as you originally planned:
X = 0
For I = 1 To 3
J = 2
For K = 1 To J * 2 Step 1
X = X + 1
Debug.Print X
Next K
Next I
Function convertToText(ByVal data As String) As String
Dim result As String = Nothing
Dim i As Integer = 0
Dim j As Integer = 0
For Each c As Char In data.ToCharArray
j *= 2
If c = "1"c Then j += 1
i += 1
If i = 8 Then
i = 0
result &= Chr(j)
j = 0
End If
Next
Return result
End Function
It converts binary to text but its a bit difficult for me to understand the logic behind it.
Someone please help.
The code seems to convert a text containing a binary number representing 8 bit character codes to a string containing these characters.
The for each loop loops over all binary digits ("0" or "1") of the input. The code of each result character is computed and after every 8 input characters the code is considered to be complete and the new character whose code was determined is added to the result (result &= Chr(j) is the same as result = result & Chr(j). Chr(j) converts an Integer containing a character code into a character). The variable i counts the bits.
The variable j holds the character code. If a bit is "1", then 1 is added to j (j += 1 is the same as j = j + 1), but not if it is "0".
A "1" in the right most bit position has a (decimal) value of 1. The next to its left a value of 2. The next 4 and so on. The value doubles for each position until it reaches 128 for the left most bit of an 8 bit number. Therefore j is doubled on each loop (j *= 2 is the same as j = j * 2).
Example with just 4 bits:
data = "1010"
The binary number 1010 means
1 * 8 + 0 * 4 + 1 * 2 + 0 * 1 = (decimal)10
The code does this
j = 0 => 0
j *= 2 => 0
j += 1 => 1 'since c = "1"
j *= 2 => 2
'no += 1 since c = "0"
j *= 2 => 4
j += 1 => 5 'since c = "1"
j *= 2 => 10
'no += 1 since c = "0"
The first 1 we added is doubled 3 times and becomes 8. The second 1 we added is doubled only once and becomes 2. 8 + 2 = 10.
I have this crazy array.
ReDim arrayDeCeldas(filas - 1, columnas - 1)
For i = 0 To filas - 1
For j = 0 To columnas - 1
arrayDeCeldas(i, j) = i & j
Debug.Write(arrayDeCeldas(i, j) & " ")
Next j
Debug.WriteLine("")
Next i
And I'm trying to link it to a number of conditions and is not well to do
I'm trying to try to get 6 index from array
The number can't repeat and it are pick horizontally or vertically randomly
0 1 2 3 4 5 6 7
10 11 12 13 14 15 16 17
20 21 22 23 24 25 26 27
30 31 32 33 34 35 36 37
40 41 42 43 44 45 46 47
This example about i'm try.
It can be seen, there are a total of 6 items with different sizes
Actually my code, it's getting huge
Private Sub setBarco()
Dim numeroRandom As New System.Random()
Dim indiceA, indiceB As Integer
For b = 1 To barcos
Randomize()
Dim value As Integer = CInt(Int((2 * Rnd() + 1)))
indiceA = numeroRandom.Next(0, filas)
indiceB = numeroRandom.Next(0, columnas)
Select Case b
Case 1
If arrayDeCeldas(indiceA, indiceB) = 0 Then
arrayDeCeldas(indiceA, indiceB) = b & 1
End If
Case 2
Select Case value
Case 1
For c = 0 To 1
If indiceB + c < columnas Then
If arrayDeCeldas(indiceA, indiceB + c) = 0 Then
arrayDeCeldas(indiceA, indiceB + c) = b & c
End If
Else
If arrayDeCeldas(indiceA, indiceB - c) = 0 Then
arrayDeCeldas(indiceA, indiceB - c) = b & c
End If
End If
Next
Case 2
For c = 0 To 1
If indiceA + c < filas Then
If arrayDeCeldas(indiceA + c, indiceB) = 0 Then
arrayDeCeldas(indiceA + c, indiceB) = b & c
Else
End If
Else
End If
Next
End Select
Case 3
Case 4
Case 5
Case 6
End Select
Next b
End Sub
Based on your comment-reply, I understand the program must:
Pick at random any six elements from a 2D-array, and each element or value must be selected only once.
That's fairly straightforward: here's a pseudo-code implementation:
Perform some initial computation:
Get the bounds of the 2D array
Seed a random number generator:
Create a HashSet instance
Get six pairs of coordinates:
Loop continuously until HashSet has 6 elements in it:
Generate a coordinate pair within the bounds of the array found in Step 1.
Get the value from the coordinate pair
Check to see if we've seen the value before (by looking at the HashSet). If we've not seen it before, then add it to the HashSet and continue, otherwise ignore it and try again.
Return the contents of the HashSet
In C# this would be:
Int32[,] numbers = new Int32[] { ... };
Int32 maxY = numbers.GetUpperBound(0); // y-axis in dimension 0
Int32 maxX = numbers.GetUpperBound(1); // x-axis in dimension 1
Random rng = new Random();
HashSet<Int32> values = new HashSet<Int32>();
while( values.Count < 6 ) {
Int32 x = rng.Next( maxX + 1 ); // Random.Next is upperbound exclusive, hence +1
Int32 y = rng.Next( maxY + 1 );
Int32 value = numbers[ y, x ];
if( !values.Contains( value ) ) values.Add( value );
}
return values.ToArray();
Note that by keeping track of observed values, instead of coordinates, we can simultaneously avoid duplicate values and duplicate coordinates: as duplicate coordinates will give you duplicate values anyway.
I'm very new to VBA and programming, so this might be a dumb question. I have written the following code:
Function central(X)
Dim xc(300, 10), xa(200)
m = X.Rows.Count
n = X.Columns.Count
For j = 1 To n
xa(j) = 0
For i = 1 To m
xa(j) = xa(j) + X(i, j)
Next i
xa(j) = xa(j) / m
For i = 1 To m
xc(i, j) = X(i, j) - xa(j)
Next i
Next
central = xc()
End Function
This should output a matrix whose elements are subtracted from the average value of their columns.
My problem is that the output is shifted with one row and column. So for example for this table:
1 1 1
2 2 2
3 3 3
it gives me:
0 0 0
0 -1 -1
0 0 0
Thanks in advance!