Sum of input number with do loops until - vb.net

Question

Quick problem on my homework. I have to make a version of this code will "Do Until Loop". The first part regarding the "please enter a positive number" works, but not the second part, that calculates the sum.
Sub Main()
Dim sumOdd, oddinput As Integer
Dim odd = 1
Console.Write("Please Enter a Positive Odd Number!: ")
oddinput = CInt(Console.ReadLine())
Do Until oddinput < 0 Or oddinput Mod 2 = 0
Console.Write("Please Enter a Positive Odd Number!: ")
oddinput = CInt(Console.ReadLine())
Loop
'The do until loop below is giving me the issue
Do Until odd <= oddinput
sumOdd += odd
odd += 2
Loop
Console.WriteLine("The Sum of all the odd numbers up to {0} is {1}!", oddinput, sumOdd)
Console.ReadLine()
End Sub
End Module

Answer 1

The first part actually does not do what you want it to.
oddinput < 0
will accept any number smaller than zero
oddinput Mod 2 = 0
will accept any even number, not odd.
But what you want is to ask the user to enter a number until it is positive and odd:
Do Until oddinput > 0 And oddinput Mod 2 = 1
Console.Write("Please Enter a Positive Odd Number!: ")
oddinput = CInt(Console.ReadLine())
Loop
For the second part you want it to add odd numbers until odd is bigger than oddinput, then stop.
Do Until odd > oddinput
sumOdd += odd
odd += 2
Loop
In your last assignment you had to use While loop so you could say: while odd is smaller or equal the final number. Here you do basically the opposite: Do until odd is bigger than the final number.
Also do not use >= as the loop would stop when odd is the same as the final number, but you want this one still to be added.

Answer 2

Try:
Do Until oddinput < 0 Or oddinput Mod 2 = 1
You were asking for an odd number, but the condition only accepted an even one.
And:
Do Until odd > oddinput
Previously, with odd = 1 and the condition odd <= oddinput, for any oddinput bigger than 1, the loop would have just exited.

Answer 3

You should initialize sumOdd at the begining.
sumOdd=0
And odd should start with 2 and not 1
Dim odd = 2
Replace also this line:
Do Until odd > oddinput
That will work. After that you need to verify the validation because it's validating for example the -2.