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iOS Object-Oriented Objective-C Tying it All Together Cumulative Review

Posted by davema
davema
2,836 Points

What is the correct answer?

What am I doing wrong here? This code seems to work in Xcode to determine the average.

variable_assignment.mm 
NSArray *temps = @[@75.5, @83.3, @96, @99.7];
float average;
float sum = 0;

    for (NSNumber *number in temps) {
        sum = sum + [number floatValue];
        average = sum/temps.count;
    }

3 Answers

jcorum
jcorum
71,830 Points

This was one of the strangest things. The only error I could see with your code is that you were computing the average inside of the loop. So I tried this:

    NSArray *temps = @[@75.5, @83.3, @96, @99.7];
    float average;
    float sum;

    for (NSNumber *number in temps) {
        sum += [number floatValue];
    }
    average = sum/temps.count;

and the Editor said I was trying to redefine sum!!??

So I tried this:

    NSArray *temps = @[@75.5, @83.3, @96, @99.7];
    float average;
    float sumx;

    for (NSNumber *number in temps) {
        sumx += [number floatValue];
    }
    average = sumx/temps.count;

and the Editor accepted it. Wow!

Happy coding.

Jason Anders
MOD
Jason Anders
Treehouse Moderator 145,858 Points
Jason Anders
Jason Anders
Treehouse Moderator 145,858 Points

I encountered this as well. "sum" is not a reserved keyword as far as I know, so I am wondering if this has something to do with the code checker for the challenge. Maybe Gabe Nadel could provide some insight on why 'sum' produces an error.

:dizzy:

Gabe Nadel
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Gabe Nadel
Treehouse Guest Teacher
Gabe Nadel
.a{fill-rule:evenodd;}techdegree
Gabe Nadel
Treehouse Guest Teacher

Indeed, this was an issue with our code challenge engine. I've changed the question a bit so it should be ok going forward. Thanks y'all for helping to make this experience better and better!