Saving Form Values After Submission in PHP

Suppose we have a form that submits to the current page:

<form action="" method="GET">
	<input name="test">
	<input type="submit">
</form>

Let's make it so that after submission the entered data does not disappear from our input:

<form action="" method="GET">
	<input name="test" value="<?php echo $_GET['test'] ?>">
	<input type="submit">
</form>

This approach, however, is not perfect - on the first visit to the page, PHP will throw an error because $_GET['test'] does not exist.

To solve the problem, let's add a condition:

<form action="" method="GET">
	<input
		name="test"
		value="<?php if (isset($_GET['test'])) echo $_GET['test'] ?>"
	>
	<input type="submit">
</form>

Using a form, ask the user for their city and country. After submitting the form, display the entered data on the screen. Make sure the entered data does not disappear from the inputs after form submission.