Double Cannot Be Dereferenced Error In Java
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up “double Cannot be Dereferenced” toString() - does this alternative form without errors mean the same thing? up vote 0 down vote favorite In the following snippet of code the int returns properly, but when I try doing the same thing with a double NetBeans 8.0.2 complains that "double Cannot be Dereferenced" The non-commented out variables work. The commented out variables are java long cannot be dereferenced double and do not work. @Override public String toString() { return "[" + getAccountNumber() + "], " + super.toString() + ", " + owner.toString() // Error: "Double Cannot be Dereferenced" why? // + ", " + currentBalance.toString() // + ", " + interestRate.toString() ; } When I rewrite it like this NetBeans doesn't give me an error, but is this effectively the same thing for a double? @Override public String toString() { return "[" + getAccountNumber() + "], " + super.toString() + ", " + owner.toString() // Error: "Double Cannot be Dereferenced" // + ", " + currentBalance.toString() // + ", " + interestRate.toString() // The following seems to work instead: + ", " + Double.toString(currentBalance) + ", " + Double.toString(interestRate) ; } If so, great. No errors. If not, what can I do to make sure that the value of a double returns to the String just as an int would? UPDATE: From the answers I received, it looks like second approach I used works, but the following works just as well: @Override public String toString() { return "[" + getAccountNumber() + "], " +
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hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join double cannot be dereferenced intvalue the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Double cannot be dereferenced…? up http://stackoverflow.com/questions/32741911/double-cannot-be-dereferenced-tostring-does-this-alternative-form-without vote 1 down vote favorite import java.awt.Rectangle; import java.util.Comparator; public class RectangleComparator implements Comparator { public int compare(Object object1, Object object2) { Rectangle rec1 = (Rectangle) object1; Rectangle rec2 = (Rectangle) object2; return rec1.getWidth().compareTo(rec2.getWidth()); } } For some reason, I'm getting the error double cannot be dereferenced. Can anyone help me figure out why? java share|improve this question edited Sep 9 '13 at 4:56 asked http://stackoverflow.com/questions/18691643/double-cannot-be-dereferenced Sep 9 '13 at 4:50 user2760309 3314 BTW, it's rarely a good idea to compare float/double values for exact equality. See stackoverflow.com/questions/4915462/… –sleske Sep 9 '13 at 5:00 add a comment| 3 Answers 3 active oldest votes up vote 3 down vote accepted rocketboy is correct with regard to why this is happening. Consider using the Double wrapper class like this new Double(rec1.getWidth()).compareTo(rec2.getWidth()); Only the first value need to be converted to a wrapper Double, the second one will be auto boxed. share|improve this answer answered Sep 9 '13 at 4:56 Thihara 4,99411538 1 You should not use new Double(…) at all. Please get into the habit of using Double.valueOf(…) as this will allow Java to reuse existing objects. Of course that’s even more important for small integers or longs. –Michael Piefel Sep 9 '13 at 6:39 @MichaelPiefel Does this depend on the implementation or am I missing something? The Double.valueOf(double d) seem to be just calling new Double(double d) under the wraps. –Thihara Sep 9 '13 at 7:15 That’s correct (for my Oracle JDK) – but it just might be better, as the comment there suggests.
This Site Careers Other all forums Forum: Beginning Java double cannot be dereferenced Accela Moon Greenhorn Posts: 20 posted 12 years ago https://coderanch.com/t/396212/java/java/double-dereferenced Hi, can someone briefly explain what does this error mean? http://www.dreamincode.net/forums/topic/286310-double-cannot-be-dereferenced/ And how to solve it? Thanks. public double price=clientObj.processedObj.price; inputLine = new JTextField (this.price.toString(), 20); inputLine.setBounds (145,210,130,25); inputPanel.add (inputLine); Error: C:\Documents and Settings\Moon\My Documents\Navi Projects\School\ OOPJ Project\Prototype\GPS-Lite v2 Alpha Debugger\SUBSCRIPTION.java:77: double cannot be dereferenced inputLine = new JTextField (this.price.toString(), 20); [ edited to cannot be break long lines -ds ] [ April 18, 2004: Message edited by: Dirk Schreckmann ] Mike Gershman Ranch Hand Posts: 1272 posted 12 years ago this.price is a double, a numeric primitive, not an object. primitives don't have methods. if this.price were a Double, this.price.toString() would work. Mike Gershman SCJP 1.4, SCWCD in cannot be dereferenced process Warren Dew blacksmith Ranch Hand Posts: 1332 2 posted 12 years ago I think you're getting the error because the primitive types - including 'double' - are not objects; they cannot have members, and in particular, don't have a toString() member method. Thus, you can't say price.toString(). Try Double.toString(price). Accela Moon Greenhorn Posts: 20 posted 12 years ago I can use such a method, its listed in the double class in java specs from java webbie, I've imported java.lang.Double.. John Smith Ranch Hand Posts: 2937 posted 12 years ago I can use such a method, its listed in the double class in java specs from java webbie, I've imported java.lang.Double In Java there is double, and there is Double. The former one is a primitive type that has no methods, and the latter is a wrapper class that extends Number and Object, and subsequently has the corresponding methods. In your code, you can use either o
12 Replies - 6205 Views - Last Post: 23 July 2012 - 05:30 AM Rate Topic: #1 BlackFiredDragon New D.I.C Head Reputation: 0 Posts: 32 Joined: 19-July 12 double cannot be dereferenced Posted 19 July 2012 - 09:10 AM I have an error with this code. It was supposed to use the binary search method in order to find the number 45.3 in this array: [-3, 10, 5, 24, 45.3, 10.5}. At first everything was OK. But then I had a problem with the decimals - because I used 'int'. So I changed a few things and made it 'double' instead of int. Now I get these errors: program-3.java:12: error: double cannot be dereferenced if (a[mid].compareTo (x)<0) ^ program-3.java:14: error: double cannot be dereferenced else if (a[mid].compareTo (x) > 0) ^ 2 errors This is my code: class Binarys { public static final int NOT_FOUND = -1; public static double binarys(double[] a, double x) { int low=0; int high = a.length - 1; int mid; while (low <= high) { mid = (low + high) / 2; if (a[mid].compareTo (x)<0) low = mid + 1; else if (a[mid].compareTo (x) > 0) high = mid - 1; else return mid; } return NOT_FOUND; } public static void main(String[] args) { double[] array = {-3, 10, 5, 24, 45.3, 10.5}; int l = array.length; int a; System.out.println("Original Numbers:"); for (a = 0; a < l; a++ ) { System.out.println(array[a]); } System.out.println("45.3 found at " + binarys(array, 45.3)); } } Please help me with this problem, it's been stuck with me for several days. Thank you! Is This A Good Question/Topic? 0 Back to top MultiQuote Quote + Reply Replies To: double cannot be dereferenced #2 macosxnerd101 Games, Graphs, and Auctions Reputation: 11994 Posts: 44,812 Joined: 27-December 08 Re: double cannot be dereferenced Posted 19 July 2012 - 09:12 AM You can't invoke methods or reference fields on primitives. Since these are numbers, just directly compare them using the >, >= , <, <=, ==, and != operators. You don't need the compareTo() method. Was This Post Helpful? 1 Back to top MultiQuote Quote + Reply #3 Ryano121 D.I.C Lover Reputation: 1460 Posts: 3,286 Joined: 30-January 11 Re: double cannot be dereferenced Posted 19 July 2012 - 09:13 AM You need to use the static method compare inside the Double class instead - if(Double.compare(a[mid], x) < 0) { ... Was This Post Helpful? 1 Back to top MultiQuote Quote + Reply #4 BlackFiredDragon New D.I.C Head Reputation: 0 Posts: 32 Joined: 19-July 12 Re: double cannot be dereferenced Posted 19 July 2012 - 09:47 AM Ryano121, on 19 July 2012 - 09:13 AM, said: