1.Variables
Transkript
1.Variables
3. HAFTA DERS 1.Variables In PHP, variables can be declared anywhere in the script. The scope of a variable is the part of the script where the variable can be referenced/used. PHP has three different variable scopes: local global static Global <?php $x = 5; // global scope function myTest() { // using x inside this function will generate an error echo "<p>Variable x inside function is: $x</p>"; } myTest(); echo "<p>Variable x outside function is: $x</p>"; ?> Local <?php function myTest() { $x = 5; // local scope echo "<p>Variable x inside function is: $x</p>"; } myTest(); // using x outside the function will generate an error echo "<p>Variable x outside function is: $x</p>"; ?> Global in Function1 <?php $x = 5; $y = 10; function myTest() { global $x, $y; $y = $x + $y; } myTest(); echo $y; // outputs 15 ?> Global in Function2 <?php $x = 5; $y = 10; function myTest() { $GLOBALS['y'] = $GLOBALS['x'] + $GLOBALS['y']; } myTest(); echo $y; // outputs 15 ?> PHP The static Keyword Normally, when a function is completed/executed, all of its variables are deleted. However, sometimes we want a local variable NOT to be deleted. We need it for a further job. <?php function myTest() { static $x = 0; echo $x; $x++; } myTest(); myTest(); myTest(); ?> 2.Constants Constants are like variables except that once they are defined they cannot be changed or undefined Syntax : define(name, value, case-insensitive) Parameters: name: Specifies the name of the constant value: Specifies the value of the constant case-insensitive: Specifies whether the constant name should be caseinsensitive. Default is false <?php define("GREETING", "Welcome to W3Schools.com!", true); echo greeting; ?> Constants are Global <?php define("GREETING", "Welcome to W3Schools.com!"); function myTest() { echo GREETING; } myTest(); ?> 3.Operators Arithmetic operators /Aritmetic Assignment operators / Atama Comparison operators / Karşılaştırma Increment/Decrement operators / Artırma Eksiltme Logical operators / Mantıksal String operators / String Array operators / Dizi Arithmetic Operators Operator Name Example Result + Addition $x + $y Sum of $x and $y - Subtraction $x - $y Difference of $x and $y * Multiplication $x * $y Product of $x and $y / Division $x / $y Quotient of $x and $y % Modulus $x % $y Remainder of $x divided by $y ** Exponentiation $x ** $y Modunu alma Result of raising $x to the $y'th Üssünü alma Assignment Operators Assignment x=y Same as... x=y Description The left operand gets set to the value of the expression on the right x += y x = x + y Toplama Addition x -= y x=x–y Çıkarma Subtraction x *= y x = x * y Çarpma Multiplication x /= y x = x / y Bölme Division x %= y x = x % y Modunu alma Modulus Comparison Operators Operator Name Example Result == Equal Değeri Eşittir $x == $y Returns true if $x is equal to $y === type Identical Tipi Eşittir $x === $y Returns true if $x is equal to $y, and they are of the same != Not equal Eşit Değil $x != $y Returns true if $x is not equal to $y <> Not equal Eşit Değil $x <> $y Returns true if $x is not equal to $y !== Not identical same type Tipi Eşittir değil $x !== $y Returns true if $x is not equal to $y, or they are not of the > Greater than $x > $y Returns true if $x is greater than $y < Less than $x < $y Returns true if $x is less than $y >= Greater than or equal to $x >= $y Returns true if $x is greater than or equal to $y <= Less than or equal to $x <= $y Returns true if $x is less than or equal to $y Increment Artırma / Decrement Eksiltme Operators Operator Name Description ++$x Pre-increment Increments $x by one, then returns $x $x++ Post-increment Returns $x, then increments $x by one --$x Pre-decrement Decrements $x by one, then returns $x $x-- Post-decrement Returns $x, then decrements $x by one $a=5; $b=6; $c= $a+ $b++ -> $c=11 $b=7; $c= $a+ ++$b -> $c=12 $b=7; Logical Operators Operator Name Example Result Show it and ve And $x and $y True if both $x and $y are true && ve And $x && $y True if both $x and $y are true or veya Or $x or $y True if either $x or $y is true || veya Or $x || $y True if either $x or $y is true True true -> true True false -> true False true ->true xor Xor $x xor $y True false -> true True if either $x or $y is true, but not both karşılaştırmanın her iki tarafı doğru olmamalı sadece birinin doğru olması gerekir False true ->true ! Not !$x True if $x is not true String Operators Operator Name Example Result Concatenation of $txt1 and $txt2 . Concatenation $txt1 . $txt2 .= Concatenation assignment $txt1 .= $txt2 Appends $txt2 to $txt1 $a=”Ali”; $b=”Can”; . . $a=$a $b -> $a=”Ali Can” olur yada $a =$b -> $a=”Ali Can” olur Array Operators DİZİ Operator Name Example Result Show it + Birleştirme Union $x + $y Union of $x and $y == Equality Returns true if $x and $y have the same key/value pairs $x == $y === Identity $x === $y and of the same types Returns true if $x and $y have the same key/value pairs in the same order != Inequality $x != $y Returns true if $x is not equal to $y <> Inequality $x <> $y Returns true if $x is not equal to $y !== Non-identity $x !== $y Returns true if $x is not identical to $y 4.if...else...elseif Statements Syntax if (condition) { code to be executed if condition is true; } if statement - executes some code if one condition is true if...else statement - executes some code if a condition is true and another code if that condition is false if...elseif....else statement - executes different codes for more than two conditions <?php $t = date("H"); if ($t < "10") { echo "Have a good morning!"; } elseif ($t < "20") { echo "Have a good day!"; } else { echo "Have a good night!"; } ?> 5.switch Statement Syntax switch (n) { case label1: code to be break; case label2: code to be break; case label3: code to be break; ... default: code to be } executed if n=label1; executed if n=label2; executed if n=label3; executed if n is different from all labels; Example <?php $favcolor = "red"; switch ($favcolor) case "red": echo "Your break; case "blue": echo "Your break; case "green": echo "Your break; default: echo "Your } ?> { favorite color is red!"; favorite color is blue!"; favorite color is green!"; favorite color is neither red, blue, nor green!"; 6.PROGRAM KODLARI <!DOCTYPE html> <html> <head> <title>Php Ders2</title> <meta http-equiv=”Content-Type” content=”text/html; charset=iso-8859-9″ /> </head> <body> <?php /* Değişkenler local global static */ echo "<br>__________Global kullanımı_______<br>"; $x=5; function test() { echo "Fonksiyon içinde değeri :".$x."<br>"; } test(); echo "Fonksiyon dışında değeri:".$x."<br>"; echo "<br>__________Local kullanımı_______<br>"; function test2() { $y=5; echo "Fonksiyon içinde değeri :".$y."<br>"; } test2(); echo "Fonksiyon dışında değeri:".$y."<br>"; echo "<br>__________Global çağrılması 1_______<br>"; $a=5; $b=10; function test3() { global $a,$b; // Global değişkenlerin çağrılması, $a=$a+$b; echo "İşlemin Sonucu :".$a."<br>"; } test3(); echo "<br>__________Global çağrılması 2_______<br>"; $k=5; $l=10; function test4() { $m = $GLOBALS['k'] + $GLOBALS['l']; // Global değişken çağrılması echo "İşlemin Sonucu :".$m."<br>"; } test4(); // **************** STATIC DEĞİŞKEN KULLANIMI**** // Fonksiyon içindeki local değişkenlerin son halini tutar echo "<br>__________satatic değişken kullanımı_______<br>"; function test5() { static $n=0; $n++; echo "n değeri = $n <br>"; } test5(); test5(); test5(); test5(); // *******************CONSTANT KULLANIMI****************** // Pogram içerisinde bir kere tanımlanıp değeri değişmeyen sabitlerdir // syntax : define("adı","değeri", true/false büyüj küçük harf duyarlılığı) echo "<br>__________CONSTANT KULLANIMI_______<br>"; define("dataserver","data.osym.gov.tr",true); echo "Data server adresi :".dataserver."<br>"; echo "Data server adresi :".DataServer."<br>"; echo "<br>"; ?> </body> </html>