I'm new to php and need some help, I am trying to take the user input and format it so that the output shows the last day of the month. Here's what I have so far:

```
<?php
    //form for user-input
    echo "<form name='form' method='post' action='array.php'>";
    echo "<p>Enter Date in ' Month/Day/Year ' format<p>";
    echo "<input type='text' id='date-input' name='date-input' placeholder='Enter date' />";
    echo "</form>";

    //grab user-input
    $input=$_POST["date-input"];

    //output in correct format
    echo $input->format("m/t/Y");

?>

```

When I have just echo input variable without the format function and date format then it displays what the user inputs, but how it's set right now; nothing displays and I get this line:

```
Fatal error: Call to a member function format() on string in C:\xampp\htdocs\php-sessions\session-3\array.php on line 190

```

Line 190 is my echo input line.