PHP Introductory tutorials for custom function usage (create, invoke, variable, parameter, return value, etc.) _php tips

This example describes the use of PHP custom functions. Share to everyone for your reference, specific as follows:

demo1.php

<?php
  //standard function, built-in function
  echo MD5 (' 123456 ');
  Echo ' <br/> ';
  echo SHA1 (' 123456 ');
  Echo ' Read who asked you to chant, water fell fragrance floating. ';
? >

demo2.php

<?php
  //create function, not with the system's built-in function name
  //function has a feature, must be called to execute
  //no parameter representation () inside is empty, no return is the function of the program no
  returns function functionname () {
    echo ' I am a functions without arguments and no returns. ';
  }
  functionname ();
? >

demo3.php

<?php
  ///contains functions with no return value for parameters//In general
  , write functions that do not need to
  be modified//changed are generally incoming parameters
  function Functionarea ($radius) {
    $area = $radius * $radius * PI ();
    The echo ' radius is '. $radius. ' Area is: '. $area;
  }
  Call
  Functionarea (a);
? >

demo4.php

<?php
  //contains parameters, with return value
  function Functionarea ($radius) {
    $area = $radius * $radius * PI ();
    return $area;
  }
  Call
  //This greatly enhances the flexibility of the function
  //functionarea (20); The whole gets a value in memory.
  the echo ' radius of 20 is: '. Functionarea
>

demo5.php

<?php
  //contains parameters, with return value//
  This $radius = 10, where 10 indicates the default value of this parameter
  //If the calling function does not pass a parameter to the function, then the default value function is enabled
  Functionarea ($radius = ten) {
    $area = $radius * $radius * PI ();
    return $area;
  }
  Call
  //This greatly enhances the flexibility of the function
  //functionarea (20); The whole gets a value in memory.
  the area of echo ' Radius 20 is: '. Functionarea ();
? >

demo6.php

<?php//
  write a function where the function returns three data functions
  functioninfo ($name, $age, $job) {
    //$userInfo is the array
    //$ UserInfo = Array ($name, $age, $job);
    $userInfo [] = $name;
    $userInfo [] = $age;
    $userInfo [] = $job;
    return $userInfo;
  }
  Call function
  Print_r (Functioninfo (' One-stop web site ', 19, ' Programmer '));
$arr = Functioninfo (' One-stop-doing website ', 19, ' Programmer ');
echo $arr [0];
List ($name, $age, $job) = Functioninfo (' One-stop web site ', 19, ' Programmer ');
echo $name. ' This year '. $age, ' He was a '. $job;
>

demo7.php

<?php
  //Before the reference, are by the value of the reference
  $prices =;
  $tax = 0.5;
  This function does not have any value, is currently in the value
  of the parameters//function variables and functions outside the variables have no relationship function
  functionprices (& $prices,& $tax) {
    //inside of $ Prices this variable is already
    $prices = $prices + $prices * $tax;
    $tax = $tax * $tax;
    echo $prices;//75
    echo ' <br/> ';
    echo $tax;//0.25
    echo ' <br/> ';
  }
  Functionprices ($prices, $tax)  ;
  Citing this concept, we are currently unable to grasp, will be in OOP time, focus on the
  echo $prices,//By value 50, by reference to become the
  echo ' <br/> ';
  echo $tax;
? >

demo8.php

<?php
  //Understanding global variable
  //can set $a to global variable
  $a = 5;
  function fa () {
    global $a;//set $a as global variable
    $a = 2;
  }
  FA ();
  echo $a;  2
?>

demo9.php

<?php
  //Using Super global variable
  $GLOBALS [' a '] = 5;
  function fa () {
    $GLOBALS [' a '] = 2;
  }
  FA ();
  echo $GLOBALS [' a '];
  Print_r ($GLOBALS [' a ']);
? >

demo10.php

<?php
  //This sentence contains the function to include
  ' library/tool.library.php ';
  Echo Functionpi ();
? >

demo11.php

The <?php
  //include () statement contains and runs the specified file.
//include ' demo1.php ';
Include ' demo1.php ';
  The include_once () statement contains and runs the specified file during the execution of the script.
  //This behavior is similar to the include () statement, except that if the code in the file is already contained, it is not included again.
//include_once ' demo1.php ';
Include_once ' demo1.php ';  Contains only referenced files once
  //include if it does not exist, tell you two warnings, and then continue to execute
  //require if not stored, directly to the error, and then stop the implementation of the
  require ' demo1.php ';
  We recommend the use of require
//require ' demo1.php ';
Require_once ' demo1.php ';
Require_once ' demo1.php ';
  Echo ' <strong> read who asked you to chant, water fall fragrance floating. </strong> '
?>

demo12.php

<?php
  //__file__
  /Magic constant--here's a constant that's just a value./
/$file = __file__;//c:\appserv\www\basic7\demo12.php
//echo $file;
  As a result, it is recommended that you use __file__ for faster
  echo dirname (__file__) When you include files,//c:\appserv\www\basic7 require (dirname
  __).' \demo1.php ');//c:\appserv\www\basic7
  echo __line__;
  function ffff () {return
    __function__;
  }
  Echo '  
 

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