Dave Angel, 17.04.2010 10:47:
Alan Gauld wrote:
"Lie Ryan" wrote
A friend of mine suggested me to do the next experiment in python
and Java.
It's a simple program to sum all the numbers from 0 to 1000000000.
result = i = 0
while i < 1000000000:
result += i
i += 1
print result
Are you sure you're not causing Java to overflow here? In Java,
Arithmetic Overflow do not cause an Exception, your int will simply wrap
to the negative side.
Thats why I asked if he got a float number back.
I never thought of it just wrapping, I assumed it would convert to
floats.
It's been years, but I believe Java ints are 64 bits, on a 32bit
implementation. Just like Java strings are all unicode.
Java has a 32bit 'int' and a 64bit 'long'.
http://java.sun.com/docs/books/tutorial/java/nutsandbolts/datatypes.html
Both will work just fine for 'i', but 'result' requires a 64 bit long:
>>> 1000000000 < 2**31
True
>>> 2**31 < 499999999500000000 < 2**63
True
Stefan
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