У меня есть класс, который наследует другой класс, в моем родительском классе есть переопределяемая функция, а в подклассе есть переопределяющая функция. Обе эти функции имеют одинаковое имя. Однако, когда я вызываю функцию в объекте подкласса, родительская функция и функция в подклассе запускаются после друг друга. Я только хочу, чтобы выполнялась переопределяющая функция (в подклассе), как мне это исправить?
Родительским классом является «очередь», а подклассом - «круговая очередь». Я хочу переопределить как функцию enqueue, так и функцию dequeue.
Модуль Модуль1
Sub Main()
Dim sorq As String
Dim schoice As String
Dim qchoice As String
Dim circhoice As String
Dim prioritychoice As String
Dim st As New stack
Dim qu As New queue
Dim cir As New movingQueue
Dim pr As New priorityQueue
Do
menu1()
sorq = UCase(Console.ReadLine())
Select Case sorq
Case "A"
Do
stackmenu()
schoice = UCase(Console.ReadLine)
Select Case schoice
Case "A"
st.push()
Case "B"
st.pop()
Case "C"
st.peek()
Case "D"
st.output()
Case "E"
st.full()
Case "F"
st.empty()
End Select
Loop Until schoice = "X"
Case "B"
Do
queuemenu()
qchoice = UCase(Console.ReadLine)
Select Case qchoice
Case "A"
qu.enqueue()
Case "B"
qu.dequeue()
Case "C"
qu.output()
Case "D"
qu.full()
Case "E"
qu.empty()
End Select
Loop Until qchoice = "X"
Case "C"
Do
circularmenu()
circhoice = UCase(Console.ReadLine)
Select Case circhoice
Case "A"
cir.enqueue()
Case "B"
cir.dequeue()
Case "C"
cir.output()
Case "D"
cir.full()
Case "E"
cir.empty()
End Select
Loop Until circhoice = "X"
Case "D"
Do
prioritymenu()
prioritychoice = UCase(Console.ReadLine)
Select Case prioritychoice
Case "A"
End Select
Loop
End Select
Loop Until sorq = "X"
Console.ReadLine()
End Sub
Sub menu1()
Console.WriteLine("What program would you like to access? A. Stack B. Queue C. Circular queue D. Priority queue X. Exit")
Console.WriteLine()
End Sub
Sub stackmenu()
Console.WriteLine("You are currently in the stack program, what would you like to do? A. Push B. Pop C. Peek D. Output stack E. Check full F. Check empty X. Exit to main menu")
Console.WriteLine()
End Sub
Sub queuemenu()
Console.WriteLine("You are currently in the queue program, what would you like to do? A. Enqueue B. Dequeue C. Output queue D. Check full E. Check empty X. Exit to main menu")
Console.WriteLine()
End Sub
Sub circularmenu()
Console.WriteLine("You are currently in the circular queue program, what would you want to do? A. Enqueue B. Dequeue C. Output queue D. Check full E. Check empty X. Exit")
End Sub
Sub prioritymenu()
Console.WriteLine("You are currently in the priority queue program, what would you like to do? A. Enqueue B. Dequeue C. Output queue D. Check full E. Check empty X. Exit")
Console.WriteLine()
End Sub
Public Class stack
Public names(4) As String
Private nextfreeslot As Integer = 0
Public Function pop() As String
Dim popped As String
If empty() = False Then
nextfreeslot = nextfreeslot - 1
popped = names(nextfreeslot)
Console.WriteLine("Removed from stack: " & popped)
Else
Console.WriteLine("No data can be removed")
End If
Return popped
End Function
Public Function push() As Integer
If full() = False Then
Console.WriteLine("Enter the name would you like to add to the stack")
names(nextfreeslot) = Console.ReadLine
nextfreeslot += 1
Else
Console.WriteLine("No data can be added")
End If
Return nextfreeslot
End Function
Public Function peek() As Integer
If empty() = False Then
Console.WriteLine("The top item in the stack is: " & names(nextfreeslot - 1))
Else
Console.WriteLine("There is no item at the top")
End If
Return peek
End Function
Public Function output() As Integer
If empty() = True Then
Console.WriteLine("The stack is empty")
Else
Console.WriteLine("Stack contents, from bottom to top: ")
For x = 0 To 4
Console.WriteLine(names(x))
Next
End If
Return output
End Function
Public Function full() As Boolean
If nextfreeslot = 5 Then
Console.WriteLine("Stack is full")
Return True
Else
Console.WriteLine("Stack is not full")
Return False
End If
End Function
Public Function empty() As Boolean
If nextfreeslot = 0 Then
Console.WriteLine("Stack is empty")
Return True
Else
Console.WriteLine("Stack is not empty")
Return False
End If
End Function
End Class
Public Class queue
Public names(4) As String
Protected tail As Integer = 0
Protected head As Integer = 0
Public Overridable Function dequeue()
Dim removed As String
If empty() = False Then
removed = names(head)
Console.WriteLine("Removed from queue: " & removed)
head += 1
Return removed
Else
Console.WriteLine("Cannot dequeue")
Return False
End If
End Function
Public Overridable Function enqueue() As Integer
If full() = False Then
Console.WriteLine("Enter the names you want to add to the queue")
names(tail) = Console.ReadLine
tail += 1
Else
Console.WriteLine("Cannot enqueue any more names")
End If
Return tail
End Function
Public Function output() As String
If empty() = True Then
Else
Console.WriteLine("Contents to queue from top to bottom")
For x = head To (tail - 1)
Console.WriteLine(names(x))
Next
End If
Return output
End Function
Public Function full() As Boolean
If tail > 4 Then
Console.WriteLine("Queue is full")
Return True
Else
Console.WriteLine("Queue is not full")
Return False
End If
End Function
Public Function empty() As Boolean
If tail = head Then
Console.WriteLine("Queue is empty")
Return True
Else
Console.WriteLine("Queue is not empty")
Return False
End If
End Function
End Class
Public Class movingQueue
Inherits queue
Public Overrides Function dequeue()
Dim removed As String
If head = tail Then
Console.WriteLine("Circular queue is empty")
ElseIf head = 4 Then
removed = names(head)
Console.WriteLine("Removed from circular queue: " & removed)
head = 0
Else
removed = names(tail)
Console.WriteLine("Removed from circular queue: " & removed)
head += 1
End If
Return MyBase.dequeue
End Function
Public Overrides Function enqueue() As Integer
If tail = 4 Then
If head > 0 Then
Console.WriteLine("What would you like to add to the circular queue?")
names(tail) = Console.ReadLine()
tail = 0
End If
ElseIf tail <> (head - 1) Then
Console.WriteLine("What would you like to add to the circular queue?")
names(tail) = Console.ReadLine()
tail += 1
Else
Console.WriteLine("Circular queue is full")
End If
Return MyBase.enqueue
End Function
End Class
Public Class priorityQueue
Inherits queue
Private priority As Integer
Function setPriority()
Console.WriteLine("Please select a priority for this data item: A. First B. Second C. Third")
priority = Console.ReadLine()
Return priority
End Function
Public Overrides Function enqueue() As Integer
Return MyBase.enqueue()
End Function
End Class
Конечный модуль