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
• Tim Cooke
• Devaka Cooray
• Ron McLeod
• Jeanne Boyarsky
Sheriffs:
• Liutauras Vilda
• paul wheaton
• Junilu Lacar
Saloon Keepers:
• Tim Moores
• Stephan van Hulst
• Piet Souris
• Carey Brown
• Tim Holloway
Bartenders:
• Martijn Verburg
• Frits Walraven
• Himai Minh

# Math.round(-4.5)=-4; Why?

Greenhorn
Posts: 8
• Number of slices to send:
Optional 'thank-you' note:
Math.round(4.5)=5;Math.round(-4.6)=-5;
Why Math.round(-4.5)=-4??
I am confused!
Thank you!

Ranch Hand
Posts: 3271
• Number of slices to send:
Optional 'thank-you' note:
From the API:

Returns the closest int to the argument. The result is rounded to an integer by adding 1/2, taking the floor of the result, and casting the result to type int. In other words, the result is equal to the value of the expression:
(int)Math.floor(a + 0.5f)

Corey
[ March 05, 2002: Message edited by: Corey McGlone ]

Author & Gold Digger
Posts: 7617
6
• Number of slices to send:
Optional 'thank-you' note:
Math.round(double d) computes and returns the following:
(long)floor(d + 0.5d);
so:
floor(4.5 + 0.5d) = 5
floor(-4.6 + 0.5d) = -5
floor(-4.5 + 0.5d) = -4

Ben Gao
Greenhorn
Posts: 8
• Number of slices to send:
Optional 'thank-you' note:
Thank you!

 Hey, I'm supposed to be the guide! Wait up! No fair! You have the tiny ad! the value of filler advertising in 2021 https://coderanch.com/t/730886/filler-advertising