Comparison of Java and C++: Difference between revisions

Revision as of 05:06, 4 February 2025

Revision as of 05:11, 4 February 2025

Line 112:

|-

| <syntaxhighlight lang="cpp">

class Foo { // Declares class Foo

int x = 0; // Private Member variable. It will

// be initialized to 0, if the

// constructor would not set it.

// (from C++11)

public:

Foo(): x{0} // Constructor for Foo; initializes

{} // x to 0. If the initializer were

// omitted, the variable would

// be initialized to the value that

// has been given at declaration of x.

int bar(int i) { // Member function bar()

return 3 * i + x;

}

};</syntaxhighlight>

| <syntaxhighlight lang="java">

class Foo { // Defines class Foo

private int x; // Member variable, normally declared

// as private to enforce encapsulation

// initialized to 0 by default

public Foo() { // Constructor for Foo

} // no-arg constructor supplied by default

public int bar(int i) { // Member method bar()

Line 245:

// outputs 5, because d references the

// same object as c</syntaxhighlight>

|}

* In C++, it is possible to declare a pointer or reference to a [[const]] object in order to prevent client code from modifying it. Functions and methods can also guarantee that they will not modify the object pointed to by a pointer by using the "const" keyword. This enforces [[const-correctness]].

* In Java, the <code>final</code> keyword is similar to the <code>const</code> keyword in C++, but its usage is more limited.{{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§3.4.1 Final fields|p=48}} For the most part, const-correctness must rely on the semantics of the class' interface, i.e., it is not strongly enforced, except for public data members that are labeled <code>final</code>.

{| class="wikitable"

! style="width:600px;"| C++

! style="width:600px;"| Java

|-

*| In C++, itIt is possible to declare a pointer or reference to a [[const]] object in order to prevent client code from modifying it. Functions and methods can also guarantee that they will not modify the object pointed to by a pointer by using the "const" keyword. This enforces [[const-correctness]].

| <syntaxhighlight lang="cpp">

const Foo* a; // it is not possible to modify the object

// pointed to by a through a

</syntaxhighlight>

|<syntaxhighlight lang="java">

*| In Java, theThe <code>final</code> keyword is similar to the <code>const</code> keyword in C++, but its usage is more limited.{{sfn|Goetz|Peierls|Bloch|Bowbeer|2006|loc=§3.4.1 Final fields|p=48}} For the most part, const-correctness must rely on the semantics of the class' interface, i.e., it is not strongly enforced, except for public data members that are labeled <code>final</code>.

|<syntaxhighlight lang="java">

final Foo a; // a declaration of a "final" reference:

// it is possible to modify the object,