personListSortedByAge.ps1

Set-StrictMode -Version Latest

<#
    Declare Person Object
#>
class person 
{

  [string]               $name;

  [datetime]             $dob;

  [Nullable[DateTime]]   $dateofLeaving;

  [char]                 $gender;

  [int]                  $age;

}

<#
    Declare Variables
#>
[System.Collections.ArrayList] $listofPersons = $null;
[string] $title = "";
[int]    $numberofPersonsToFetch =0;

<#
    Set Variables
#>
$numberofPersonsToFetch =1;

<#
    Instanciate Collection ( $listofPersons )
#>
$listofPersons = New-Object -TypeName "System.Collections.ArrayList";

<#
    Function:- addPerson
#>
function addPerson
(
      [string]             $name `
      
    , [datetime]           $dob `
    
    , [char]               $gender `
    
    , [Nullable[DateTime]] $dateofLeaving
    
)
{
    
    <#
        Declare local variables
    #>
    [Nullable[DateTime]] $dtReferenceAge = $null;
    
    <#
        Instanciate person object
    #>
    $obj = [person]::new();   
    
    <# 
        Set Class Property
    #>
    $obj.name = $name;
    
    $obj.dob = $dob;
         
    $obj.gender = $gender;   
    
    <#
        If date of leaving is indicated
            please use the date provided as base for calculating age
        else 
            use current date  
    #>
    if ($dateofLeaving -ne $null )
    {
     
        $obj.dateofLeaving = $dateofLeaving;
        
        $dtReferenceAge = $dateofLeaving;
    
    }
    else
    {
        $dtReferenceAge = [datetime]::Now;
    }


    <#
        https://stackoverflow.com/questions/14959399/powershell-getting-a-persons-age   
    #>        
    
        <#
            Get timestamp between reference date and dob
        #>
        $span = $dtReferenceAge - $dob
    
        $ageSpan = New-Object DateTime -ArgumentList $Span.Ticks;
        
            $obj.age = $ageSpan.year -1;

        $ageSpan = $null;
        
    $null = $listofPersons.add($obj);
    
}


function displaySectionHeader([string] $title)
{
    [int] $len =0;
    
    [char]   $CHAR_HYPHEN = "-";
    [string] $underline ="";
    
    $len = $title.length;
    
    $underline = [String]::new($CHAR_HYPHEN, $len);
    
    Write-Host $title;
    
    Write-Host $underline;
    
    
}
<#
    Add persons
    https://en.wikipedia.org/wiki/Mae_Jemison
#>
$null = addPerson "Mae Jemison" "1956-10-17" "F" $null

#https://en.wikipedia.org/wiki/Ricki_Lake
$null = addPerson "Ricki Lake" "1968-12-21" "F" $null

# https://en.wikipedia.org/wiki/Lauren_Lake
$null = addPerson "Lauren Lake" "1969-07-12" "F" $null

# https://en.wikipedia.org/wiki/John_Lewis
$null = addPerson "John Lewis" "1940-02-21" "M" "2020-06-17"

# https://en.wikipedia.org/wiki/Sidney_Poitier
$null = addPerson "Sidney Portier" "1927-02-20" "M" "2022-01-06"


<#
    List all persons
#>
$title = "Persons";
displaySectionHeader $title;

$listofPersons| 

    select name, dob, gender, dateofLeaving | 
    
    Sort name |
    
    Format-Table * -AutoSize

    
Write-Host "";


Write-Host "";

<#
    Get oldest person
        a) based on date of birth
#>
$title = "Oldest Person";
displaySectionHeader $title;

$listofPersons| 

    Sort dob |   

    select -first ($numberofPersonsToFetch)`
                name `
              , @{Name = "date of birth"; Expression = { "{0:yyyy-MMM-dd}" -f ($_.dob ) } } `
              , @{Name = 'gender'; Expression = {"{0,-6}" -f ($_.gender ) }}`
              , @{Name = "date of leaving"; Expression = { "{0:yyyy-MMM-dd}" -f ($_.dateofLeaving ) } } `
              , @{Name = "age"; Expression = { ( $_.age) } }  |              
    
    Format-Table * -AutoSize
    

Write-Host "";


Write-Host "";

<#
    Get oldest person
        a) based on date of birth
        b) filter out departed
#>
$title = "Oldest Person - Leave out departed";
displaySectionHeader $title;

$listofPersons| 

    Where-Object { ( $_.dateofLeaving -eq $null ) } |

    Sort dob |   

    select -first ($numberofPersonsToFetch)`
                name `
              , @{Name = "date of birth"; Expression = { "{0:yyyy-MMM-dd}" -f ($_.dob ) } } `
              , @{Name = 'gender'; Expression = {"{0,-6}" -f ($_.gender ) }}`
              , @{Name = "age"; Expression = { ( $_.age) } }  |
              
    
    Format-Table * -AutoSize
    

Write-Host "";


Write-Host "";

<#
    Get oldest person
        a) based on date of birth
        b) filter out departed
        d) only females
#>

$title = "Oldest Person - Leave out departed, Gender has to be female";
displaySectionHeader $title;

$listofPersons| 

    Where-Object { ( $_.dateofLeaving -eq $null ) } |
    
    Where-Object gender -eq "f" |
    
    Sort dob |   

    select -first ($numberofPersonsToFetch)`
                name `
              , @{Name = "date of birth"; Expression = { "{0:yyyy-MMM-dd}" -f ($_.dob ) } } `
              , @{Name = 'gender'; Expression = {"{0,-6}" -f ($_.gender ) }}`
              , @{Name = "age"; Expression = { ( $_.age ) } }  |
    
    Format-Table * -AutoSize