What is the difference between PHP functions and Java functions?

In PHP and Java, the main difference between functions is: parameter passing: PHP passes by value, Java passes by reference. Return value: PHP can return explicitly or not, Java must return a value matching the declaration. Access control: None for PHP, public, protected, default, private for Java. Anonymous functions: supported by PHP, not supported by Java. Optional parameters: PHP supports, Java only supports setting when declaring.

The difference between PHP functions and Java functions

In PHP and Java, two popular programming languages, functions play an important role character of. Although both languages ​​allow functions to be defined and used, they differ in some ways.

Declaration Syntax

• PHP：

  function function_name([parameters]) {
  // 函数体
  }

• Java:

  public static void function_name([parameters]) {
  // 函数体
  }

Parameter passing

• ##PHP: Parameters are passed by value by default.
• Java: Pass parameters by reference (value) by default.

Return value

• PHP: A function can explicitly return a value or return no value (void).
• Java: The function must return a value whose type matches the return value type specified in the function declaration or void.

Access Control

• PHP: Function has no explicit access control modifier.
• Java: Functions can be declared as public, protected, default (package-private) or private.

Practical case

Consider the following function in PHP and Java to find the sum of two numbers:

• PHP:

  function add($a, $b) {
  return $a + $b;
  }

• Java:

  public static int add(int a, int b) {
  return a + b;
  }

In PHP, pass to add( ) The parameters of the function are values, and the return value is the summation result. In Java, parameters are passed by reference, which means that modifications to the parameters within a function affect the value of the variable when the function is called.

Other Differences

• PHP: Functions can be anonymous functions or closures.
• Java: Functions must have names and cannot be anonymous functions or closures.
• PHP: Functions can have optional parameters and default parameter values.
• Java: Functions can only use optional parameters in the function declaration, and default parameter values ​​cannot be specified.

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