initalizing vars when declaring functions (Java VS C++)

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Hi all,

I'm new to java and i'm trying to figure out if we could assign values to variables when declaring a function.

Here is some explanation (Correct me if i'm wrong)

in C++ We could write:

C#

class Humain 
{
public:
    String nom;
    int age;
public:
    Humain(int age, String name): age(age), name(name){}
}

I'm wondering if we could write in java like that.

PS: i looked in many web sites and all used as below

Java

Humain(int age, String name){
   this.age = age;
   this. name = name;
}

Thank you.

Posted 26-Apr-12 0:10am

Schehaider_Aymen

Updated 26-Apr-12 0:39am

v2

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enhzflep 26-Apr-12 6:29am

I'm almost certain I'm being unnecessarily pedantic - but since 1 misplaced character in MBs of source code can kill a program, I thought it pertinent to mention that the c++ class definition should read: (Sorry, not sure of the equivalent in Java)

class Humain
{
public:
Humain(int age, string name): age(age), nom(name){}
private:
string nom;
int age;
};

Schehaider_Aymen 26-Apr-12 6:38am

yeah you saif right but i pasted the code from a java test prog that i wrote so i missed the public: and all went private in my example :) but still not the subject here.

Thank you for the remarque

V2: Updated

Richard MacCutchan 26-Apr-12 6:54am

I don't think that syntax exists in Java; what happens when you try it?

Schehaider_Aymen 26-Apr-12 7:13am

it gives several errors beginning with :

I have to implement the function age ... so i thought that may be it exists but i wrote it wrong

Richard MacCutchan 26-Apr-12 7:38am

beginning with ... ?

Schehaider_Aymen 26-Apr-12 10:08am

sorry i meant "starting by" not in the sens of "starting with :"

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Aescleal · Answer 1 · 2012-04-26T02:48:00

Solution 1

Unlike C++ you can specify initial values in your class but you can't use an initialiser list. Quite what that does for performance I don't know but I assume the compiler removes redundant initialisation.

Cheers,

Ash

PS: Have you got a copy of "The Java Programming Language" by Arnold, Gosling and Holmes? If not grab a copy, it's got answers like this in it. (That's where I got the answer to this question BTW).

Posted 26-Apr-12 2:48am

Aescleal

Updated 26-Apr-12 2:50am

v2

Comments

Schehaider_Aymen 26-Apr-12 10:16am

Could you tell me the section number from wich you got the answer?

Thank you.

Espen Harlinn 26-Apr-12 10:36am

N3242 - 12.6.1-8

Espen Harlinn 26-Apr-12 10:34am

Have a 5 even if this is now valid C++:

struct C {
C() { } // initializes members as follows:
int i; // OK: i has indeterminate value
int j = 5; // OK: j has the value 5
};

/* C++11 feature */

Aescleal 26-Apr-12 20:18pm

cool, I'll have to have a play with that!