Java Program example to demonstrate variable length of arguments

Program

public class VarArgList
{
	void varTest(int ... arg)
	{
		System.out.println("Number of arguments:\t" + arg.length);
		System.out.println("Arguments are:");
		int i = 1;
		for(int x : arg)
		{
			System.out.println("arg[" + i +  "] : " + x);
			i++;
		}
		System.out.println();
	}
	public static void main(String[] args)
	{
		VarArgList argLst = new VarArgList();
		argLst.varTest(100);
		argLst.varTest(10, 20, 30);
		argLst.varTest();
	}
}

This Java program demonstrates the concept of variable-length arguments (varargs) using the int ... arg syntax.

1. Variable-Length Arguments (int ... arg):

   • The method varTest accepts a variable number of integer arguments.
   • The ... in the method parameter allows the method to take zero or more arguments of the specified type (int in this case).
   • Internally, the variable-length arguments are treated as an array.

2. varTest Method:

   • Count of Arguments: The method uses arg.length to find the number of arguments passed.
   • Display Arguments: It iterates over the arguments using an enhanced for loop and prints each argument with its index.

3. main Method:

   • Creates an instance of the VarArgList class.
   • Invokes the varTest method with different numbers of arguments:
     • A single argument: argLst.varTest(100);
     • Multiple arguments: argLst.varTest(10, 20, 30);
     • No arguments: argLst.varTest();

4. Varargs Syntax:

   • The ... syntax allows a method to accept zero or more arguments of a specified type.
   • Varargs are internally treated as an array.

5. Flexibility:

   • The program demonstrates how a single method can handle different numbers of inputs without requiring multiple overloaded methods.

Advantages of Varargs:

• Simplifies method definitions by eliminating the need for method overloading.
• Provides flexibility for accepting varying numbers of arguments.

**Output 1**
```shell
Number of arguments:	1
Arguments are:
arg[1] : 100

Output 2

Number of arguments:	3
Arguments are:
arg[1] : 10
arg[2] : 20
arg[3] : 30

Output 3

Number of arguments:	0
Arguments are: