Questions: PHP First Program

What is the extension of a PHP file?

.php is the extension of a PHP file.

Is it necessary for a file to have the correct extension for the PHP engine to be able to execute it?

No. If we have a file called program.txt that contains PHP code and then try executing it, the PHP engine won't complain at all.

What is the significance of <?php and ?> in a PHP file?

They denote PHP code in a PHP file.

What is the echo keyword?

The echo keyword is a means of outputting text to the standard output stream in PHP.

What is a string?

A string is a sequence of characters that denotes literal text in a program.

Give one way to denote a string in PHP.

Using a pair of single quotes ('').

What is the php.exe file that comes with the installation of PHP and what is its purpose?

php.exe is an executable program that is meant to parse and execute PHP code. Sometimes it's also referred to as the PHP interpreter, or the PHP engine.