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![VARIABLES
Variables are declared memory that contains
data during execution.
Rules to declare variable_
Only $, [A-Z, a-z], [0-9] and underscore are
allowed.
Every name must preceded by the $ sign.
After the $ sign there must be an alphabet or
underscore.
E.g. $var_name, $varName, $abc123, $_1234 etc
are some valid declaration.](https://image.slidesharecdn.com/2basicsofphp-170215181627/85/basics-of-php-9-320.jpg)
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basics of php
- 1.
- 2. CONTENTS… HOW CANYOUWRITEYOURSCRIPTS? RUNNING A PHP SCRIPT DATATYPES VARIABLES CONSTANTS OPERATORS
- 3. HOW CAN YOUWRITE YOUR SCRIPTS? The PHP Scripts are embedded in an HTML page in three following ways. XML style <? Php // php scripts ?>
- 4. CONTINUED… Short Style <? //php scripts ?>
- 5. CONTINUED… Script Style <scriptlanguage = “php”> // php scripts </script>
- 6. CONTINUED… Example: <html> <head> <title>Introduction PHP</title> </head> <body> <?php echo“Introduction to PHP”; ?> </body> </html>
- 7. RUNNING A PHPSCRIPT Save your script in the root directory of your web server say as “DEMO.php”. Open the web browser and type the following URL http://localhost/DEMO.php Refresh your browser. You will see the output.
- 8. DATA TYPES Datatype tells about the behavior of data. In PHP there are following data types_ Integers Float numbers Strings Boolean Arrays Objects Resources Null
- 9. VARIABLES Variables aredeclared memory that contains data during execution. Rules to declare variable_ Only $, [A-Z, a-z], [0-9] and underscore are allowed. Every name must preceded by the $ sign. After the $ sign there must be an alphabet or underscore. E.g. $var_name, $varName, $abc123, $_1234 etc are some valid declaration.
- 10. CONTINUED… For assigningvalues into the variables we use the = sign. E.g. $var = 10; $varWord=‘PHP tutorial’; Assigning value from one variable to another. E.g. $var1=$var; Destroying variables when they are not required_ E.g. unset($var);
- 11. CONTINUED… Printing valuesfrom variables E.g. <?php $x = 10;$word = ‘PHP’; echo “variable x = ”$x,”n variable word = ”$word; print $x; ?> note: print is used for formatted output.
- 12. CONSTANTS Constants arethe values those never alter during the program run. There are a lot of constants are predefined in PHP. E.g. M_PI defines the value of ∏. Defining constants in PHP E.g. <?php define(“ConstantName”, constantValue); echo “ConstantName”; ?>
- 13. OPERATORS Operators Symbol Assignment Operators= Arithmetic Operators + - * / % -(negation) Compound Assignment Operators += -= *= /= %= .= Relational operators == != <> === !== < > <= >= String Operators . Logical Operators && || xor and or Increment and Decrement operators ++ --
- 14. THANKS Prev : Introduction PHP. Next:Control program flow