An example of PHP's automatic type conversion is the addition operator '+'.

 
<?
$foo = "0"; 
$foo++; 
$foo += 1; 
$foo = $foo + 1.3; 
$foo = 5 + "10 L"; 
$foo = 5 + "10 S"; 
?>

1.	Arithmetic Operators
2.	Arithmetical Operators
3.	Changing the default precedence using parentheses
4.	Increment/decrement Operators
5.	Incrementing and decrementing
6.	Using the autodecrement operator
7.	Using the negation operator
8.	Using pre- and postincrement
9.	Using autoincrement to add to a variable
10.	Postfix and Prefix Operators summary table
11.	Peculiarities of the ++ and -- Operators
12.	postfix and prefix increment operators also work on letter values
13.	Postfix and Prefix Operators in Action
14.	Calculation Results for Postfix and Prefix Operators
15.	Shorthand Operators summary table
16.	Variables Are Assigned by Value
17.	Using Assignment Operators

An example of PHP's automatic type conversion is the addition operator '+'. : Arithmetic Operators « Operator « PHP