I need to make a console app for a class, and it has to compute the following using a For Next loop: 4 + 8 + 12 + 16 + 20 .... + 208
Here's what I have:
Dim x As Integer = 0
Dim z As Integer = 4
For x = 0 To 208 Step 4
z = z + 4
Console.WriteLine(z)
Next
I have no idea what I'm doing wrong.
On each iteration, you are adding 4 to z, so you are actually computing 4 + 4 + 4 + ... + 4. What you really want to do is to add x to z:
Dim x As Integer = 0
Dim z As Integer = 4
For x = 0 To 208 Step 4
z = z + x
Console.WriteLine(z)
Next
Related
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
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
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.
How can I get the multiples of 3 or 5 in vb.net? I have this code but it gives me different output. Please help me.
Dim x As Integer
For x = 3 To 10
If x Mod 2 <> 0 Then
Dim sum As Integer
sum += x
MsgBox(x)
End If
Next
The output will be 3,5,7,9. The expected output should be 3,5,6,9. So any help?
x Mod 2 <> 0 gives you all numbers except numbers that are divisible by 2. But you want all numbers that are divisible by 3 or 5.
So this gives you the expected output:
For x = 3 To 9
If x Mod 3 = 0 OrElse x Mod 5 = 0 Then
' ... '
Note that my loops ends with 9 instead of 10 since 10 would be divisible by 5 but you dont expect it.
For Each i As Integer In Enumerable.Range(1,10) _
.Where(Function(i) i Mod 3 = 0 OrElse i Mod 5 = 0)
MsgBox(i)
Next i
Why do you check x Mod 2 <> 0, when you need multiplies of 3 and 5? Try following:
Dim x As Integer
For x = 3 To 10
If x Mod 3 = 0 OrElse x Mod 5 = 0 Then
Dim sum As Integer
sum += x
MsgBox(x)
End If
Next
I tried to google the answer for this but could not find it. I am working on VB.Net. I would like to know what does the operator += mean in VB.Net ?
It means that you want to add the value to the existing value of the variable. So, for instance:
Dim x As Integer = 1
x += 2 ' x now equals 3
In other words, it would be the same as doing this:
Dim x As Integer = 1
x = x + 2 ' x now equals 3
For future reference, you can see the complete list of VB.NET operators on the MSDN.
a += b
is equivalent to
a = a + b
In other words, it adds to the current value.
It is plus equals. What it does is take the same variable, adds it with the right hand number (using the + operator), and then assigns it back to the variable. For example,
Dim a As Integer
Dim x As Integer
x = 1
a = 1
x += 2
a = a + 2
if x = a then
MsgBox("This will print!")
endif
those 2 lines compiled produce the same IL code:
x += 1
and
x = x + 1
Just makes code more efficient -
Dim x as integer = 3
x += 1
'x = 4
is the same as
x = x + 1
'x = 4
It can also be used with a (-):
x -= 1
' x = 2
Is the same as
x = x - 1
'x = 2