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var-args

TUSHAR KADAM answered on November 22, 2022 Popularity 9/10 Helpfulness 3/10

answer var-args

var-args

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--var-args (Variable Argument)-
-var-args allows the method to accept zero or multiple arguments.
-before var-args we use overloaded method or take array as method parameter,but
        it is bad practice + maintenance problems
-don't know how many arguments will have to pass in method--> var-args is better approach.

-Syntax- var-args uses 'ellipsis' i.e. three dots after data type.
-[accessModifier] returnType methodName(datatype...variableName){
    
}

-eg. class Main{
    
    static void disply(String...values)
    {
        //accessing the elements from var-args
        for(String s : values)
        {
            System.out.println(s);
        }
    }
    
    public static void main(String args[])
    {
        display(); //zero argument
        display("my","name","is","var-args"); //four arguments
    }
}

--Rules of var-args
-1.there can be only one variable argument in the method.
void method(String...a, int...b){} //compile time error(rule no.1)
-2.var-args must be last argument if we have any other arguments are there
void method(int...a, String b){} //compile time error(rule no.2)

-class Main{
    static void display(int num, String... values)
    {
        System.out.println("number is "+num);
        for(String s:values)
        {
            System.out.println(s);
        }
    }

    public static void main(String args[])
    {
        display(200);//zero var-arg
        display(500,"hello");//one var-args
        display(1000,"my","name","is","varargs");//four var-args
    }
}

-static void display(int...arr)
display(null); // error
int[] arr = {10,20,30};
display(arr);
display(10,20,30);

-if multiple overloaded methods are there then var-args gets least priority.
    1. public static int add(int...arr)
    2. public static int add(int i)
    add(10); //in main method
    -> second method will be called.
    
-along with var-args we cannot define another overloaded method which takes array of the
same type parameter, it will become duplicate method definition.

Popularity 9/10 Helpfulness 3/10 Language java

Source: Grepper

Tags: arguments java

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Contributed on Nov 22 2022

TUSHAR KADAM

0 Answers Avg Quality 2/10

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