Need assistance with powershell script - powershell

Question

See code below
##If user inputs %100 or a100 or non-numeric value for temp, I need to display "Error: You must enter a numeric Value!" Write-host $("Error: You must enter a numeric Value!")
## then goes back to start
##im guessing if ($value isnot [int]) or something like that for it to work. thank you.
##Error I get without proper coding......What is the temperature in Fahrenheit: a111
##Cannot convert value "a111" to type "System. Single". Error: "Input string was not in a ##correct format."
Write-Host("="*31)
Write-Host $("Fahrenheit to Celsius Converter")
Write-Host $("Script Written By Jesse ")
Write-Host("="*31)
$value = (Read-Host("What is the temperature in Fahrenheit"))
$fahr = (($value -32) /9) *5
Write-Host $("Fahrenheit", $value, "is equal to Celsius:", [Math]::Round($fahr,3))
$input = (Read-Host("Do you want to convert another Fahrenheit value? (1 = yes, 0 = no)?"))
Write-Host ("="*31)
while ($input)
{
if ($input -eq 1)
{
Write-Host $("Fahrenheit to Celsius Converter")
Write-Host $("Script Written By Jesse Nieto ")
Write-Host ("="*31)
$value = (Read-Host("What is the temperature in Fahrenheit"))
$fahr = (($value -32) /9) *5
Write-Host $("Fahrenheit", $value ,"is equal to Celsius:" ,[Math]::Round($fahr,3))
$input = (Read-Host("Do you want to convert another Fahrenheit value? (1 = yes, 0 = no)?"))
Write-Host("="*31)
}
elseif ($input -eq 0)
{
Write-Host $("Thank You. Bye! ")
break
}
else
{
Write-Host $("Please enter a valid option! ")
$input = (Read-Host ("Do you want to convert another Fahrenheit value? (1 = yes, 0 = no)?"))
Write-Host ("="*31)
}
}

Answer 1

There is much redundant code on your script which could be simplified, the biggest issue is the use of $input which is an automatic variable and should not be assigned manually. As for the formula to convert from Fahrenheit to Celsius, you could use a function for that, as aside, according to Google, the formula should be (X − 32) × 5 / 9 though I'm not an expert on this, feel free to change for whatever you like.
function ConvertTo-Celsius {
param([int]$Value)
($value - 32) * 5 / 9
}
:outer while($true) {
$value = Read-Host "What is the temperature in Fahrenheit"
try {
$celsius = ConvertTo-Celsius $value
}
catch {
# If input was invalid restart the loop
Write-Host "Invalid input, only integers allowed!"
continue
}
Write-Host "Fahrenheit $value°F is equal to $([math]::Round($celsius, 3))°C"
do {
$shouldExit = Read-Host "Do you want to convert another Fahrenheit value? (1 = yes, 0 = no)?"
switch($shouldExit) {
0 {
Write-Host "Thank You. Bye!"
break outer
}
1 { continue }
Default { Write-Host "Please enter a valid option!" }
}
} until($shouldExit -eq 1)
}