Variable argument or varargs in Java
Variable argument or varargs in Java allows
you to write more flexible methods which can accept as many argument as you
need. variable arguments or varargs were added in Java 1.5 Variable
arguments is a useful for a developer. Some
time we have a scenario that one method can take variable number of
argument and now with varargs from language makes it much easier.
Variable
arguments before Java 1.5
Prior to Java 1.5 if a Java programmer needs to
send multiple arguments to a method, they mainly have two choices to :
1. Either overload the method.
2. Take an array or Collection and pass the no of
argument wrapped in array or Collection like List, Set or Map.
The real challenge for a developer comes when the
developer is not aware about the number of arguments to handle and how many
overloaded methods will be created. This will result in long and clumsy code,
which again can be error prone if the developer has missed including the method
with specific number of argument in the code.
This is where in varargs comes into picture.
varargs or variable arguments makes it possible for
the developer to call one method with
variable number of argument; means define only one method and call that method
with zero or more argument.
Syntax:
type … variable Name.
Ellipses stands for variable argument java treats
variable argument as an array of same data type. 3 dots is used to denote
variable argument in a method and if there are more than one parameter, varargs
arguments must be last, as better listed below
Some points which should be taken care when use
varargs:
- Ellipse can be used once in
method parameter list.
- Ellipse with type must be used
in parameter list at the end of the method
Example
to illustrate Varargs
public class Example01 {
public static int add(int ...var){
int sum=0;
for(int i:var)
sum+=i;
return sum;
}
public static void main(String[] args) {
System.out.println("Sum of 1
and 2 is = " +add(1,2));
System.out.println("Sum of
1, 2 and 3 is = " + add(1,2,3));
System.out.println("Sum of
1, 2, 3 and 4 is = "+add(1,2,3,4));
}
}
Output of the Code
 |
Variable argument or varargs in Java
Original Post at : http://learnerpoint.in/2017/01/04/variable-argument-or-varargs-in-java/
|