# The string type represents text as a sequence of char values, 
# while each character is UTF-16 encoded 16-bit Unicode code point

# literal string
$sampleText = "This is a string";

# empty string
$emptyStr = "";

$x = 5

# no substitution 
Write-Host 'The value of $x is $x.' # The value $x is $x.

# substitution 
Write-Host "The value of `$x is $x." # The value $x is 5.

$title = "PowerShell block string"

# verbatim block string
$html = @'
<div>
    <h1>$title<h1>
    <p>xyz</p>
</div>
'@

Write-Host $html

Write-Host "------------------------------------"

# interpolation possible block string
$html = @"
<div>
    <h1>$title<h1>
    <p>xyz</p>
</div>
"@

Write-Host $html

$input = Read-Host "Enter something"

$isEmpty = [string]::IsNullOrEmpty($input)

Write-Host "Input is empty: $isEmpty"

Write-Host "Please enter Login Credential `r`n(Login User Id & Password)"

#
# Plain Text to Secured String
#
$securedString = ConvertTo-SecureString $plainText

$securedString = Read-Host "Enter your password" -AsSecureString

#
# From Secured String to Plain Text
#
$plainText = [Runtime.InteropServices.Marshal]::PtrToStringAuto([Runtime.InteropServices.Marshal]::SecureStringToBSTR($securedString))

$BSTR = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($Credential.Password)
$ClearTextPassword = [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($BSTR)
Write-Host $ClearTextPassword

# User defined function
function ConvertTo-String {
    param(
        [Parameter(Mandatory)]
        [Security.SecureString] $SecureString
    )
    try {
        $bstr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($SecureString)
        [Runtime.InteropServices.Marshal]::PtrToStringAuto($bstr)
    }
    finally {
        if ( $bstr -ne [IntPtr]::Zero ) {
            [Runtime.InteropServices.Marshal]::ZeroFreeBSTR($bstr)
        }
    }
}