What is difference between language constracter and function for exampal echo print in php language?

Answer 1

I think you mean language construct...

Anyway, a function usually takes one or more arguments as comma separated values or variables.

echo and print don't

<?php

$email = 'user@example.com';

$domain = strstr($email, '@');

echo $domain; // prints @example.com

?>

Here the strstr function takes a variable string and a constant string as an argument. echo simply displays the contents of the resulting variable.

There are a couple functions that don't require arguments, like die() & exit()