iOS If-else statement not evaluating

[alexatwater]

This is driving me nuts. This is a “mocked up” version of a major issue i’m having in my actual project and is really frustrating me, any help would be so much appreciated. So you can copy this exact code into a blank command line app and see my issue:

NSMutableDictionary *loadGradeDictionary = [[NSMutableDictionary alloc] initWithCapacity:11];
        [loadGradeDictionary setObject:[NSArray arrayWithObjects:@"A", @"A-", @"B+", @"B", @"B-", @"C+", @"C", @"C-", @"D+", @"D", @"D-", @"F" , nil] forKey:@"gradesArray"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (92.5 + 0.5)] forKey:@"A"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (89.5 + 0.5)] forKey:@"A-"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (86.5 + 0.5)] forKey:@"B+"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (82.5 + 0.5)] forKey:@"B"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (79.5 + 0.5)] forKey:@"B-"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (76.5 + 0.5)] forKey:@"C+"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (72.5 + 0.5)] forKey:@"C"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (69.5 + 0.5)] forKey:@"C-"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (66.5 + 0.5)] forKey:@"D+"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (62.5 + 0.5)] forKey:@"D"];
        [loadGradeDictionary setObject:[NSString stringWithFormat:@"%.2f",  (59.5 + 0.5)] forKey:@"D-"];
        NSLog(@"\n%@", loadGradeDictionary);


        float passedGrade = 90;
        NSDictionary *gradeScale = loadGradeDictionary;
        NSMutableString *returnString = [[NSMutableString alloc] initWithCapacity:2];
        NSString *xString = [NSString stringWithFormat:@"%.2f", passedGrade];

        if (([xString floatValue] > [[gradeScale valueForKey:@"A"] floatValue])) {
            //return the letter here
            returnString = [@"A" mutableCopy];
        } else if (([[gradeScale valueForKey:@"A"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"A-"] floatValue])) {
            //return the letter here
            returnString = [@"A-" mutableCopy];
            //return @"A-";
        } else if (([[gradeScale valueForKey:@"A-"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"B+"] floatValue])) {
            //return the letter here
            returnString = [@"B+" mutableCopy];
            //return @"B+";
        } else if (([[gradeScale valueForKey:@"B+"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"B"] floatValue])) {
            //return the letter here
            returnString = [@"B" mutableCopy];
            //return @"B";
        } else if (([[gradeScale valueForKey:@"B"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"B-"] floatValue])) {
            //return the letter here
            returnString = [@"B-" mutableCopy];
            //return @"B-";
        } else if (([[gradeScale valueForKey:@"B-"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"C+"] floatValue])) {
            //return the letter here
            returnString = [@"C+" mutableCopy];
            //return @"C+";
        } else if (([[gradeScale valueForKey:@"C+"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"C"] floatValue])) {
            //return the letter here
            returnString = [@"C" mutableCopy];
            //return @"C";
        } else if (([[gradeScale valueForKey:@"C"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"C-"] floatValue])) {
            //return the letter here
            returnString = [@"C-" mutableCopy];
            //return @"C-";
        } else if (([[gradeScale valueForKey:@"C-"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"D+"] floatValue])) {
            //return the letter here
            returnString = [@"D+" mutableCopy];
            //return @"D+";
        } else if (([[gradeScale valueForKey:@"D+"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"D"] floatValue])) {
            //return the letter here
            returnString = [@"D" mutableCopy];
            //return @"D";
        } else if (([[gradeScale valueForKey:@"D"] floatValue] > passedGrade) && (passedGrade > [[gradeScale valueForKey:@"D-"] floatValue])) {
            //return the letter here
            returnString = [@"D-" mutableCopy];
            //return @"D-";
        } else if ([[gradeScale valueForKey:@"D-"] floatValue] > passedGrade) {
            //return the letter here
            returnString = [@"F" mutableCopy];
            //return @"F";
        }

        NSLog(@"\nreturnString: %@", returnString);

i get a blank string at the end of it, and when you debug it and it goes to evaluate the if/else statements, it like “crashes” and blanks out, then comes back and just skipped evaluation of the whole thing. So weird and frustrating. Any help would be great!

 

[ArtOfWarfare]

Here's your problem:

passedGrade is 90.

gradeScale[@"A-"] is also 90.

because of the way your code is written, it'll enter none of those cases if passedGrade is exactly equal to any of the values.

You should use >= instead to compare the values.

Further, your code is incredibly redundant. I'd use a loop instead that looks more like this:

__block NSString *bestGradeSoFar = @"Ungraded";
    __block float bestGradeSoFarValue = 0;
    [gradeScale enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
        float consideringValue = [obj floatValue];
        if (passedGrade >= consideringValue && consideringValue > bestGradeSoFarValue) {
            bestGradeSoFar = key;
            bestGradeSoFarValue = consideringValue;
        }
    }];

I tested and this works. Just a few small changes I had to make...

1 - I replaced returnString with bestGradeSoFar... feel free to swap it back. It needs to be a __block variable, though.
2 - I removed the array from the dictionary. It's bad code smell to be having a dictionary mostly full of one type of key/value pair and then have one key/value pair with a completely different type. I don't think that kind of thing is even allowed in type-checked languages like Java. If you want to stick with that design where you have an array in there, you'll need to add in the a respondsToSelector: inside the loop to prevent it from crashing.

 

[ianray]

Nice one, ArtOfWarfare, great example of enumerateKeysAndObjectsUsingBlock usage