Not able to understand the rules of Var-args... please help...

[rizwana mujawar]

rule1)you must specify type of arguments that var-args parameter of your method can recieve
rule2)To declare a method using var-args parameter,you must follow the type with ellipsis(),space and then the name of the array that will hold the parameter recieved.
rule3)Its legal to have other parameters in a method that uses a var-args.
rule4)(This rule is confusing me the most). The var-arg must be last parameter in the methods signature,and you can have only one var-args in a method....
Can anyone explain me the 3rd and 4th rule...
void doStuff(char c,int...x) { } //this is legal
but then why below one is illegal..?
void doStuff(int ....y,char x) { }

void doStuff(String...s,byte b) { } //var-args must be last (I dint get)

Thanks...!

[Pramod P Deore]

rule4)(This rule is confusing me the most). The var-arg must be last parameter in the methods signature,and you can have only one var-args in a method....

If you have a method that takes var-arg as a parameter then var-arg must be the last parameter.
suppose you have a method that takes 2 parameter one byte and one var-arg then you can't write as

void doStuff(String...s,byte b) { } 

because here your method accepting var-arg as a first parameter. You should write it as

void doStuff(byte b,String...s) { } 

rule1)you must specify type of arguments that var-args parameter of your method can recieve

as in above code you must have to written that ypur var-arg param type is String

[rizwana mujawar]

Another doubt about var-args...
Should i always declare it void doStuff(String.....s). I mean those dots are compulsory...? or i can write it in void doStuff(String s)

[rizwana mujawar]

Thank you so much for those valuable replies:). Thanks once again:)

[Pramod P Deore]

Should i always declare it void doStuff(String.....s). I mean those dots are compulsory...? or i can write it in void doStuff(String s)

What you get when you tried? That three dots are compulsarry. Because doStuff(String.....s) and doStuff(String s) both are different methods.

doStuff(String s) => Means method is accepting only one string parameter.
But doStuff(String.....s)=> Means method can accept any number of String parameter.

Thank you so much for those valuable replies. Thanks once again

You are Welcome

[Jeff Verdegan]

Pramod P Deore wrote:

Should i always declare it void doStuff(String.....s). I mean those dots are compulsory...? or i can write it in void doStuff(String s)

What you get when you tried? That three dots are compulsarry. Because doStuff(String.....s) and doStuff(String s) both are different methods.

doStuff(String s) => Means method is accepting only one string parameter.
But doStuff(String.....s)=> Means method can accept any number of String parameter.

And the varargs one can also accept a String[] parameter.

// first one
doStuff("abc");

// second one
doStuff();
doStuff("abc");
doStuff("abc", "def", "xyz");
doStuff(new String[]{"abc", "def", "xyz"});

[Jeff Verdegan]

Pramod P Deore wrote:

Should i always declare it void doStuff(String.....s). I mean those dots are compulsory...? or i can write it in void doStuff(String s)

What you get when you tried? That three dots are compulsarry. Because doStuff(String.....s) and doStuff(String s) both are different methods.

So, yes, you can write doStuff(String s), but then it's not a varargs method.