unreachable statement error

[Asha Dore]

Can't figure out why I'm getting unreachable statement errors on my System.out.println lines. Anyone have any ideas?

public class LeapYearExpert
{
	
	
	
	public static boolean isLeapYear(int year)
	{
		
		if ((year % 4 == 0) && (year % 400 == 0) && !(year % 100 == 0))
		{
			return true;
			System.out.println(year + " is a leap year.");
		}
		
		else 
		{
			return false;
			System.out.println("Sorry! No leap year in " + year);
		}
		if ((year < 1900) && (year > 2299))
		{
			System.out.println(year + " is not a valid input.");
		}
		
		
	}


}

[Seetharaman Venkatasamy]

you end thread execution by using return, so the thread execution cant reach System.out.println, hence you are getting the expected exception.

use System.out.println, just before the return statement.

[Seetharaman Venkatasamy]

Welcome to JavaRanch Asha . Please use code tag, while posting your code, next time.

[Asha Dore]

Thanks! Sorry about using the wrong format!

[fred rosenberger]

I added the tags for you - see how much more readable it is now?

I think even if you revers your return and print statements, you still have a problem. Can you tell me what conditions you will ever reach line 20?

[Ove Lindström]

fred rosenberger wrote:Can you tell me what conditions you will ever reach line 20?

That is possible when you use the "Project leader calendar". Then you can be done about 100 years before you start... ;)

[Campbell Ritchie]

Nice one! But you need to be done 300 years before you start in this case.

Actually, that is one error the compiler probably cannot catch.

[John Jai]

fred rosenberger wrote:
Can you tell me what conditions you will ever reach line 20?
That is possible when you use the "Project leader calendar". Then you can be done about 100 years before you start... ;)

Nice one! But you need to be done 300 years before you start in this case. Actually, that is one error the compiler probably cannot catch.

Please explain these comments not able to decipher them

[Asha Dore]

Got the format right I think.

I changed it quite a bit after further reading. The program compiles and the tester runs. Everything works at this point except the output for a leap year is still saying that it's not a leap year. I'm thinking my arithmetic is way off. Or some other major issue that I'm missing

public class LeapYearExpert
{
	
	private int year;
	
	/**
	 	Constructs LeapYearExpert instance with the given year.
		@param aYear resets value for year.
	*/
	
	public LeapYearExpert(int aYear)
	{
		year = aYear;
	}
	/**
		Returns true and false boundaries for year.
		@param year is given year.
		@return true if value is true.
		@return false if value is false.
	*/
		
	
	
	public static boolean isLeapYear(int year)
	{
		
		if ((year % 4 == 0) && !(year % 100 == 0) && (year % 400 == 0))
		{
			
			return true;
			
		}
		
		
		else 
		{
	
			return false;
			
		}
	}
	/**
		Constructs String representation of LeapYearExpert instance.
		@return the String representation based on given values. 
	*/
		
	public String toString()
	{	
		if ((year % 4 == 0) && !(year % 100 == 0) && (year % 400 == 0))
		{
			return year + " is a leap year.";
		}
		
		else if ((year < 1900) || (year > 2299))
		{
			return year + " is not valid input.";
		}
		
		else
		{
			return "Sorry! No leap year in " + year;
		}
	}
		
	
	

}

import java.util.Scanner;

public class LeapYearExpertTester
{

	public static void main(String[] args)
	{
		Scanner keyboard = new Scanner(System.in);
		
		System.out.print("Year one:");
		int yearOne = keyboard.nextInt();
		
		System.out.print("Year two:");
		int yearTwo = keyboard.nextInt();
		
		System.out.print("Year three:");
		int yearThree = keyboard.nextInt();
	
		LeapYearExpert firstYear = new LeapYearExpert(yearOne);
		System.out.println(firstYear);
		
		LeapYearExpert secondYear = new LeapYearExpert(yearTwo);
		System.out.println(secondYear);
		
		LeapYearExpert thirdYear = new LeapYearExpert(yearThree);
		System.out.println(thirdYear);
		
	}


}

[Campbell Ritchie]

John Jai wrote: . . . Please explain these comments . . .

Do you really need an explanation?

[John Jai]

Check the leap year condition - i am not confident though (not thoroughly tested )

		if ((year % 400 == 0) || (!(year % 100 == 0) && (year % 4 == 0)))

Do you really need an explanation?

Yes

[fred rosenberger]

the original code had (boiled down)

if (something)
   return true;
else
   return false
do something  //<---this was effectively "line 20"

So, no matter what the original condition was, we would return from the method in either the 'if' or the 'else' block. There was no way to ever get past it without returning, so the 'line 20' is unreachable.

I think the other comments were jokes about Project Managers setting unrealistic completion dates

[Asha Dore]

John Jai wrote:Check the leap year condition - i am not confident though (not thoroughly tested )

		if ((year % 400 == 0) || (!(year % 100 == 0) && (year % 4 == 0)))

Do you really need an explanation?

Yes

Thank you SO much. That totally works. And will help me with my arithmetic in the future.

[Campbell Ritchie]

John Jai wrote: . . .

Do you really need an explanation?

Yes

You can't explain a joke.

And try (i & 3) == 0 instead of i % 4 == 0. I'll let you work out why, but it will give slightly faster execution.

[Ove Lindström]

Campbell Ritchie wrote:
And try (i & 3) == 0 instead of i % 4 == 0. I'll let you work out why, but it will give slightly faster execution.

That was a nice one.

[John Jai]

Campbell Ritchie wrote:And try (i & 3) == 0 instead of i % 4 == 0. I'll let you work out why, but it will give slightly faster execution.

I tried changing the code like below & saw execution time in milli seconds. I did not see any difference. Correct the code if its wrong

if ((year % 400 == 0) || (!(year % 100 == 0) && ((year & 3) == 0)))

I used inputs 1992, 1994 & 1996 so that every time the third condition got hit and looped for 1000 times in for loop

[Rob Spoor]

This kind of optimization is micro optimization, as the difference will hardly ever exceed microseconds, perhaps not even nanoseconds. I'd never use "& 3" because "% 4" is simply easier to understand.

[Manoj Kumar M]

dear all
i too used bitwise code found in web to optimise the performance in some areas. Can any one tell me some good technical resource to learn java bitwise operators???