Author's Code

[Randy Draper]

I trying to learn Java from "Java A Beginners Guide" Fifth Edition by Herber Schildt. In the fourth chapter he has this program that I copied and compiled but I get errors from his example. Because I am new I do not know how to fix the problems. Here is the program.

1. // Add range to Vehicle
2.
3. class Vehicle
4. {
5. 	int passengers; // number of passengers
6. 	int fuelcap; // fuel capacity in gallons
7. 	int mpg;  // fuel consumption in miles per gallon
8. 	
9. 	// Display the range
10. 	void range()
11. 	{
12. 		System.out.println("Range is " + fuelcap * mpg);
13. 	}
14. }
15. 
16. public class AddMeth 
17. {
18. 
19. 	/**
20. 	 * @param args
21. 	 */
22. 	public static void main(String[] args) 
23. 	{		
24. 		Vehicle minivan = new Vehicle();
25. 		Vehicle sportscar = new Vehicle();
26. 		
27. //		int range1, range2;
28. 		
29. 		// Assign values to fields in minivan
30. 		minivan.passengers = 7;
31. 		minivan.fuelcap = 16;
32. 		minivan.mpg = 21;
33. 		
34. 		// Assign values to fields in sportscar
35. 		sportscar.passengers = 2;
36. 		sportscar.fuelcap = 14;
37. 		sportscar.mpg = 12;
38. 		
39. 		System.out.print("Minivan can carry " + minivan.passengers + ". ");
40. 		
41. 		minivan.range();  // display range of minivan
42. 		
43. 		System.out.print("Sportscar can carry " + sportscar.passengers + ". ");
44. 		
45. 		sportscar.range(); // display range of sportscar
46. 	}
47. 
48. }

I am using the latest Eclipse and on line 3 Eclipse is saying "The type Vehicle is already defined".

On line 31 Eclipse is stating "Exception in thread "main" java.lang.NoSuchFieldError: fuelcap
at AddMeth.main(AddMeth.java:31)"

These are things I don't understand how to fix and I would like someone to help repair the code so it actually works. Thanks

Randy

[William P O'Sullivan]

Do you have these in one file?

Also, please use the codetags (I would format it for you, but I can't)

WP

[Mike Simmons]

Do you have another Vehicle.java file lying around somewhere? Or perhaps it's just a Vehicle.class file that needs to be updated. Try deleting all you .class files and recompiling.

[Campbell Ritchie]

Welcome to the Ranch

That is a pretty dreadful design you have been given, and I have seen similar in other books. The fields should have private access in the Vehicle class, and should be initialised via the constructor. If you want to display them in other classes, they can be made accessible via public getXXX methods.

[Campbell Ritchie]

You ought not to try to run anything which Eclipse tells you there is an error in.

At this stage, you are probably better off not using an IDE at all.