Check if Integer is Positive or Negative - Objective C

Question

How can I tell in objective-c coding if an integer is positive or negative. I'm doing this so that I can write an "if" statement stating that if this integer is positive then do this, and if its negative do this.

Thanks,

Kevin

Are you forgetting zero, which is neither positive nor negative? — JWWalker, Jun 17 '10 at 21:22

Paul R · Accepted Answer · 2010-06-18T11:08:51.250

38

if (x >= 0)
{
    // do positive stuff
}
else
{
    // do negative stuff
}

If you want to treat the x == 0 case separately (since 0 is neither positive nor negative), then you can do it like this:

if (x > 0)
{
    // do positive stuff
}
else if (x == 0)
{
    // do zero stuff
}
else
{
    // do negative stuff
}

edited Jun 18 '10 at 11:08

answered Jun 17 '10 at 21:19

Paul R

208,748
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5

Until they discover functions like log(x). – Eiko Jun 17 '10 at 21:31
1

@BlueRaja - Danny Pflughoeft: well it doesn't have a `-` in front of if, so that's good enough for me. ;-) – Paul R Jun 17 '10 at 21:31
8

@Deniz: Mathematicians say 0 is a *non-negative* value; but it's not *positive*. – BlueRaja - Danny Pflughoeft Jun 17 '10 at 21:37
1

@BlueRaja - Danny Pflughoeft: if...else statemens evaluate logical expressions as true/false, so for computer "if it is not negative, it is positive". – Deniz Acay Jun 17 '10 at 21:44
2

@Deniz Acay: Then please do a if(-1) printf("Wow I'm positive"); and fasten your seatbelts.... C takes everything != 0 as true. – Eiko Jun 17 '10 at 21:54
3

@Deniz Acay: I've never heard of mathematicians accepting 0 as positive (and I used to be a math professor). Mathematicians use the word "nonnegative" all the time. They wouldn't need the word if it meant the same thing as "negative". – JWWalker Jun 17 '10 at 22:32
Looks like i understood this "non-negative" word as "positive", so thanks for correction :) – Deniz Acay Jun 18 '10 at 08:29

score 3 · Answer 2 · answered Jun 17 '10 at 21:20

3

Maybe I am missing something and I don't understand the quesiton but isn't this just

if(value >= 0)
{
}
else
{
}

answered Jun 17 '10 at 21:20

Steve Sheldon

6,421
3
31
35

Eiko · Answer 3 · 2010-06-17T21:58:20.407

3

-(void) tellTheSign:(int)aNumber
{
   printf("The number is zero!\n");
   int test = 1/aNumber;
   printf("No wait... it is positive!\n");
   int test2 = 1/(aNumber - abs(aNumber));
   printf("Sorry again, it is negative!\n");
}

;-)

Seriously though, just use

if (x < 0) {
// ...
} else if (x == 0) {
// ...
} else {
// ...
}

Don't overdo methods ans properties and helper functions for trivial things.

edited Jun 17 '10 at 21:58

answered Jun 17 '10 at 21:51

Eiko

25,601
15
56
71

score 2 · Answer 4 · answered Jun 06 '19 at 12:03

2

In Swift

var value = 5
if value.signum() == 1 {
   print("Positive value")
} else if value.signum() == -1 {
   print("Negative value")
} else if value.signum() == 0 {
   print("Zero value")
}

answered Jun 06 '19 at 12:03

Sourabh Kumbhar

1,034
14
12

What is signum() here .? – Yogesh Patel Jun 20 '19 at 07:54
It is function which returns '-1' if this value is negative and '1' if it's positive otherwise, '0'. – Sourabh Kumbhar Jun 20 '19 at 08:50
is this native function or you did your self .? – Yogesh Patel Jun 20 '19 at 09:10
It's inbuilt function – Sourabh Kumbhar Jun 20 '19 at 09:51
can you please in which type this support because I working in objective-c means it Float, Int, Decimal , NSNumber .? – Yogesh Patel Jun 20 '19 at 09:52
var direct we can you in swift but objc we need to specify the type first hot you understand that please tell me so I can do this thing Thank You :) – Yogesh Patel Jun 20 '19 at 09:53
Find here so help you https://developer.apple.com/documentation/swift/int64/2886319-signum – Sourabh Kumbhar Jun 20 '19 at 09:56

Check if Integer is Positive or Negative - Objective C

4 Answers4