Added Tutorial 4 source code

Author: dima_los

tutorial-4-variables-part-1/.htaccess

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+php_value display_errors On

tutorial-4-variables-part-1/counter.php

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+<?php
+
+$counter = 1;
+$counter = $counter + 1;
+//now counter holds 2
+$counter = $counter + 1;
+//now counter holds 3
+//and so on.

tutorial-4-variables-part-1/play.php

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+<?php
+
+$favoriteSuperHero = 'Spider man';
+$age = 16;
+
+echo $favoriteSuperHero; //shows 'Spider man' in your browser
+echo $age;//shows 16 in your browser
+
+?>

tutorial-4-variables-part-1/play_2.php

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+<?php
+
+$favoriteSuperHero = 'Spider man';
+
+echo $favoriteSuperHero;
+echo $favoriteSuperHero;
+echo $favoriteSuperHero;
+echo $favoriteSuperHero;
+echo $favoriteSuperHero;

tutorial-4-variables-part-1/play_3.php

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+<?php
+
+echo 'Spider man';
+echo 'Spider man';
+echo 'Spider man';
+echo 'Spider man';
+echo 'Spider man';

tutorial-4-variables-part-1/variable_naming_rules.php

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+<?php
+
+//valid variable names
+$email = '[email protected]';//starting with a lowercase letter
+$Email = '[email protected]';//starting with an uppercase letter
+$_avangers = false;//starting with an underscore
+$a51desert = true;//digits are allowed from the second character
+$area51 = true;
+$fullName = 'Spider Man'; //mixing lowercase and uppercase characters
+$n_e_e_d____F_o_R___speed_2 = 'Underground';//mixing underscores, lowercase, uppercase and digits
+
+/*
+//invalid variable names
+email = '[email protected]';//a variable must begin with $
+$4diablo = 'IsAwesome'; //starting variable with a digit
+$diablo-four = 'Sucks'; //using the special character '-' in the variable name
+$bg!3 = 'Amazing'; //using the special character '!' in the variable name
+$^water_melon = false; //using the special character '^' in the variable name
+$name@of_our_galaxy = 'Milky Way Galaxy'; //using the special character '@' in the variable name
+$%*__of__() = false; //using special characters '%*()' in the variable name
+*/