calculating numbers

[lovekang]

public static void main(String args[]) {
System.out.println(0.1); // 0.1
System.out.println(0.7); // 0.7
System.out.println(0.1 + 0.7); // 0.7999999999999999
}

I expect 0.1, 0.7 and 0.8
why this happens?

thanks.

 

[prosper]

//try this
System.out.println(0.1f + 0.7f); // 0.7999999999999999

 

[lovekang]

Thanks.

I'm wondering why this happens?

 

[Diancecht]

Well, it's an all computing matter: you cannot represent all numbers with a finite number of bytes.

http://forum.java.sun.com/thread.jspa?threadID=386078&messageID=1660010

Cheers,
Dian