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IBM mock

Anonymous
Ranch Hand

Joined: Nov 22, 2008
Posts: 18944
Hi all,
I got confused by the mock question:
int x1 = -1, x2 = -1; x1 = x1 >>> 31; x2 >>= 31;
what is the result:

a) x1 = -1, x2 = -1

b) x1 = 1, x2 = -1

c) x1 = 1, x2 = 1

d) x1 = 1, x2 = 0
I think none of is correct. x1=1 is correct, but x2 is not possiable to be -1, 1 or 0. For x2>>=31, the result should be 32 bits with all 1, Am I right? Please help me!
mike

Anonymous
Ranch Hand

Joined: Nov 22, 2008
Posts: 18944
I think the answer is B. The >>> is unsigned and the >> is signed.
hemanshow
Greenhorn

Joined: Jun 26, 2000
Posts: 25
x1 is 11111111111111111111111111111111 (32 1's )
x2 is 11111111111111111111111111111111 (32 1's )
x1 = x1 >>>31
x2 >>= 31;
now:
x1 = 00000000000000000000000000000001
x2 = 11111111111111111111111111111111
>>> adds o's to left.
>> adds what was already at the most significatnt bit(1's in our case)
M I right?
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: IBM mock