FIX: Comparision with Zero Generates Bad Code

 Last reviewed: January 22, 1998
Article ID: Q156913
The information in this article applies to:
  • Microsoft Visual J++ 1.0

SYMPTOMS

The following code sets the Boolean to true, whereas the correct value is false: 

   int i = 0;
   boolean b = (0 < i);
b is set to true.

CAUSE

This problem is due to bad code generated by the compiler.

WORKAROUND

Change the above code as shown below: 

   int i = 0;
   boolean b = (i > 0);

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. This problem has been fixed in Visual J++ 1.1.

MORE INFORMATION

The problem occurs only when 0 is the literal on the left side of the operator. If the left side of the operator is a variable or a literal other than 0, then the expression is evaluated correctly. The following expressions are evaluated correctly: 

   int i = 0;
   int j = 0;

   boolean b = (i < j);

   i++;

   b = (1 < i);
Some of the common places where you might run into this bug are in conditional statements or loops.

Steps to Reproduce Problem

Use the following code to reproduce the problem: 

   int i = 0;
   boolean b = (0 < i);

Additional query words: comparison

REFERENCES

For the latest Knowledge Base articles and other support information on
Visual J++ and the SDK for Java, see the following page on the
Microsoft Technical Support site:

http://support.microsoft.com/support/visualj/
http://support.microsoft.com/support/java/

Keywords : CmdLnUtils
Technology : kbInetDev
Version : 1.0
Platform : WINDOWS
Issue type : kbbug
Solution Type : kbfix

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Last reviewed: January 22, 1998
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