• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Jeanne Boyarsky
  • Ron McLeod
  • Paul Clapham
  • Liutauras Vilda
Sheriffs:
  • paul wheaton
  • Rob Spoor
  • Devaka Cooray
Saloon Keepers:
  • Stephan van Hulst
  • Tim Holloway
  • Carey Brown
  • Frits Walraven
  • Tim Moores
Bartenders:
  • Mikalai Zaikin

why is this not an infinite loop?

 
Ranch Hand
Posts: 358
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
 
Ranch Hand
Posts: 504
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
My understanding is that at some point variable b exceeds the MAX value of byte and wraps around to become negative 128, then will grow up to zero, where the loop condition fails. Correct me if I'm wrong.
 
Vad Fogel
Ranch Hand
Posts: 504
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Actually, I missed the condition ++b>0. It exits as soon as b becomes negative.
 
Sheriff
Posts: 4313
Android IntelliJ IDE Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

Originally posted by Vad Fogel:
Actually, I missed the condition ++b>0. It exits as soon as b becomes negative.


That's right -- in Java you'll never get a number overflow exception -- instead (whether good or bad) when you go beyond the upper-limit of a datatype, the numbers just wrap around wihtout any warning. The range of a byte is -128 to 127. So as soon as that loop executes 127 times, it'll wrap around to -128 and the >0 condition will fail.
 
rani bedi
Ranch Hand
Posts: 358
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Thanks. I got it now.
 
reply
    Bookmark Topic Watch Topic
  • New Topic