VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3090
   ClientLeft      =   60
   ClientTop       =   450
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3090
   ScaleWidth      =   4680
   StartUpPosition =   3  'Windows Default
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Type Vector
    x As Single
    y As Single
    z As Single
    norma As Single
End Type

Const NumVectores = 3
Const PosicionVectorSuma = 4

Private Sub Form_Load()

ReDim arrVect(1 To NumVectores) As Vector
Dim i As Integer, mensaje As String

Randomize

mensaje = "Vectores generados aleatoriamente" & vbCrLf & vbCrLf

For i = 1 To NumVectores

    'La funcion Rnd retorna un numero aleatorio mayor o igual a cero y menor que uno
    ' Por lo tanto Round(Rnd * 10,1) retorna un numero real mayor o igual a 0
    ' y menor que 10
    
    With arrVect(i)
        .x = Round(Rnd * 10, 2)
        .y = Round(Rnd * 10, 2)
        .z = Round(Rnd * 10, 2)
        
        .norma = Sqr(.x * .x + .y * .y + .z * .z)
        
        mensaje = mensaje & "Vector " & Str(i) & " : " & _
        Str(.x) & ", " & Str(.y) & ", " & Str(.z) & vbCrLf & _
        "Norma : " & Str(Round(.norma, 2)) & vbCrLf
        
    End With
    
Next i

'redimensiona el arreglo conservando su contenido

ReDim Preserve arrVect(1 To PosicionVectorSuma)

For i = 1 To NumVectores
    
    With arrVect(PosicionVectorSuma)
        .x = .x + arrVect(i).x
        .y = .y + arrVect(i).y
        .z = .z + arrVect(i).z
    End With
Next i

With arrVect(PosicionVectorSuma)
    .norma = Sqr(.x * .x + .y * .y + .z * .z)

    mensaje = mensaje & "Vector " & Str(i) & " : " & _
    Str(.x) & ", " & Str(.y) & ", " & Str(.z) & vbCrLf & _
    "Norma : " & Str(Round(.norma, 2))

End With

MsgBox mensaje

End Sub