C + + Overloaded constructors cannot be called to each other

Overloaded constructors in Java classes can call each other, as in the following code:

1  Public classTestConstructor {2     Private intvalue;3 4      PublicTestConstructor (intvalue) {5          This. Value =value;6System.out.println ("Constructor1:" + This);7     }8 9      PublicTestConstructor () {Ten          This(10); OneSystem.out.println ("Constructor2:" + This); A     } -  -      Public Static voidMain (string[] args) { theTestConstructor test =NewTestConstructor (); - System.out.println (test.value); - System.out.println (test); -     } +}

The result of the code execution is:

Constructor1:[email protected]
Constructor2:[email protected]
10
[Email protected]

The visible result is expected, the value assignment is successful, and only one object is created.

Consider the C + + implementation (header file omitted):

1#include"Testconstructor.h"2#include <QDebug>3 4 Testconstructor::testconstructor ()5 {6 //This (ten);7TestConstructor (Ten);8Qdebug () <<"Constructor1:"<< This;9 }Ten  OneTestconstructor::testconstructor (intvalue) A { -      This->value =value; -Qdebug () <<"Constructor2:"<< This; the}

1#include"Testconstructor.h"2#include <QDebug>3 4 intMainintargcChar*argv[])5 {6TestConstructor *t =NewTestConstructor ();7Qdebug () <<t->value;8Qdebug () <<T;9     DeleteT;Ten}

The result of the code execution is:

Constructor2:0x22fcf0

Constructor1:0xdadfb0

15574896

0xdadfb0

On the one hand, the value set values are not in effect, and on the other hand, two constructors create two different objects, stating that C + + cannot be called from one another in Java-like constructors.

Workaround:

The requirement for most constructors to call each other should be a default parameter, which can be set directly in the function declaration of C + + (Java does not support default parameters) so that no constructor overloads are required:

TestConstructor (int value = 10);

　　

C + + Overloaded constructors cannot be called to each other