Negative int

[visu Nekk]

Hi,

Given an int, how to determine whether it is positive or negative. For e.g. int x = -1; How to determine x is negative?

Thanks,
Visu Nekk

[Sunny Jain]

look at the bit pattern of x..!!

if right most bit is 1, this means it is negative..!!!

x = -1 ===> 11111111 11111111 11111111 11111111

[Jim Yingst]

I'm not sure the original poster was thinking of bit patterns. The answer might be as simple as

if (x < 0)
    System.out.println("negative");
else
    System.out.println("not negative");

[Sunny Jain]

if he was asking this..!! he could have tested it first..before posting!!

[Jim Yingst]

This is the beginner section. Maybe he doesn't know how to use <, or write an if statement, or print the result. Who knows?

[Paul Clapham]

And also, if the rightmost bit of a binary integer is 1, that means it's an odd integer, not that it's a negative integer.

[Campbell Ritchie]

Originally posted by Paul Clapham:
And also, if the rightmost bit of a binary integer is 1, that means it's an odd integer, not that it's a negative integer.

You mean leftmost, surely.

BTW: If you get a binary String with the Integer.toBinaryString() methods, it excludes leading 0s, so it always has 1 as the leftmost displayed digit. You will have to use a for loop and the insert method of StringBuilder (or similar) to pack it with 0s from the left.

[edit]For always has 1 read "almost always has 1" The value of 0 wouldn't have a 1 in![/edit]
[ January 30, 2008: Message edited by: Campbell Ritchie ]

[Jim Yingst]

[PC]: And also, if the rightmost bit of a binary integer is 1, that means it's an odd integer, not that it's a negative integer.

[CR]: You mean leftmost, surely.

I'm pretty sure he meant rightmost. Leftmost is what Sunny should have said, but rightmost is what he did say. Paul was commenting on that.

[Sunny Jain]

Ohh I am sorry, What I meant was left most bit..!!
Being a left handed person i often got confusion regarding that..! as My left is actually my right hand..but for other it is left hand..!!

[Campbell Ritchie]

Yes, you are right; it was Sunny Jain who ought to have said leftmost.

[Raghavan Muthu]

Originally posted by Sunny Jain:
Ohh I am sorry, What I meant was left most bit..!!
Being a left handed person i often got confusion regarding that..! as My left is actually my right hand..but for other it is left hand..!!

Good that the confusions are resolved earlier here. Also i believe it does not make any confusions wiht L-R , R-L associativities