Imports System
Imports System.Math
Module PercentChangeProgram
Function PercentChange(x As Double, y As Double) As Double
Return ((y - x) / Abs(x)) * 100.0
End Function
Function DescribeChange(x As Double, y As Double) As String
Dim pct As Double = PercentChange(x, y)
If pct > 0 Then
Return String.Format(
"From {0:F1} to {1:F1} is a {2:F2}% increase (+{2:F2}%)",
x, y, pct
)
ElseIf pct < 0 Then
Return String.Format(
"From {0:F1} to {1:F1} is a {2:F2}% decrease ({3:F2}%)",
x, y, Abs(pct), pct
)
Else
Return String.Format(
"From {0:F1} to {1:F1} is no change",
x, y
)
End If
End Function
Sub Main()
Console.WriteLine(DescribeChange(-80.0, 120.0))
Console.WriteLine(DescribeChange(120.0, 30.0))
End Sub
End Module
' run:
'
' From -80.0 to 120.0 is a 250.00% increase (+250.00%)
' From 120.0 to 30.0 is a 75.00% decrease (-75.00%)
'
