CODEWITHSUNDEEP
objective-cdoubledivisionnanmultiplication
iahmed16
iahmed16

Reputation: 3

nan double in objective c

I have this equation

double x = ((newCount/allCount)/.8)*5.0;

newCount is a double with value 0 allCount is a double with value 0

the result of x is -nan(0x8000000000000)

why this happens and how to check this value in objective c to assign default value for it

Upvotes: 0

Views: 1878

Answers (3)

trojanfoe
trojanfoe

Reputation: 122458

You are diving by zero. You can check for it using:

isnan(x)

Upvotes: 2

user23743
user23743

Reputation:

The problem is that the denominator (allCount) is 0; dividing by zero is not allowed and the answer is not a number. The simplest thing you could do is to test for that before doing the division:

if (allCount != 0) {
  x = ((newCount/allCount)/.8)*5.0
} else {
  x = defaultValue;
}

There are more complicated ways using C's floating point environment and testing for the FE_DIVBYZERO exception, but while that's standard it's rarely used and therefore potentially more difficult for a later reader of the code to comprehend.

Upvotes: 0

TheAmateurProgrammer
TheAmateurProgrammer

Reputation: 9392

allCount is a 0, thus you just divided by 0 (which is impossible if you didn't know..) So before you assign x, just make sure that allCount is not 0 first.

if (allCount != 0)
    double x = ((newCount/allCount)/.8)*5.0;

Upvotes: 0

Related Questions