New user: Enum with switch case

[Hitesh Rathod]

Hi All,

I have decided to appear for SCJP 6. And as a first unavoidable step, I have registered to Big Moose Saloon...

First of all, thank you all in advance.

Have one issue with Enum- switch case.

K&B has one example related to switch statement :

 

 enum Color {red,green,blue}

 class SwitchEnum {
	public static void main(String[] args) {
		Color c = Color.red;
		switch (c) {
		case red:
			System.out.print("red ");
		case green:
			System.out.print("green ");
		case blue:
			System.out.print("blue ");
		default:
			System.out.println("done");
		}
	}
} 

Can someone please explain the following:

1. How can we use 'red' directly in case statement without using enum name e.g. Color.red?

2. Why cant we use 'Color.red' in case statement?( It gives compile time error..)

Thanks

[Ankit Garg]

Hi Hitesh! Welcome to javaranch.

when you use enums in a switch case, it acts like as if we have imported the enum. The enum variable in the switch expression, acts as the base for all the enum constants used as the case statements...

[Edit: added welcome message ]

[Hitesh Rathod]

Hi Ankit,

Thanks for the quick reply!!!

Good to know the answer. Why are such concepts not covered in K&B? Or have i missed it while reading?

Thanks again.

[Abhi vijay]

Hi, Hitesh. K&B covers very few details about Enums. So, its upto you to make code snippets to explore the minute details of Enums. All the best.

[Jia Tan]

Can someone explain why the above code gives the output:

red green blue done

TIA

[fred rosenberger]

if you don't put a 'break' statement in, then once you enter the case, every line will be executed.

[Himalay Majumdar]

solar wind wrote:Can someone explain why the above code gives the output:

red green blue done

TIA

Since there are no break statements, whenever a particular case matches..all the following case statemets are executed regardless of a match

[Jia Tan]

Thanks Himalay for explanation.