Using multiple else if statements for NSInteger

Question

I have a section of code, in which I want a different accessoryView for the TableView cell, based off the number for that cell's entry. The code I have set up is:

NSInteger warriors = [entry.prayerWarriors intValue];

        if (warriors == 0) {
            //Do nothing
            //NSLog(@"0");
        }
        else if (0 < warriors < 50) {
            cell.accessoryView = firstLevel;
           // NSLog(@"50");

        }
        else if (51 < warriors < 100) {
            cell.accessoryView = secondLevel;
          //  NSLog(@"100");

        }
        else if (101 < warriors < 500) {
            cell.accessoryView = thirdLevel;
         //   NSLog(@"500");

        }
        else {
            cell.accessoryView = fourthLevel;
         //   NSLog(@"A Lot");

        }

However, it always returns only the first entry for warriors == 0. What am I doing wrong?

try `NSLog`ing the variable rather than a string to see what is in there. `NSLog(@"%@", warriors)` — martskins, May 08 '14 at 20:26
@lascort ok, I logged the variable, and it came back as expected...5 different numbers, one for each range of numbers. The NSLog for the ranges shows either 0 or 50 (the first two if statements), but none of the others, despite the other 3 variables being from the remaining statements. — user717452, May 08 '14 at 20:29
You've fallen into the trap of using the "natural" `x < y < z` notation for checking between bounds. That does not work (at least not how you think it should) for C or C++ or Java. — Hot Licks, May 08 '14 at 20:34

score 2 · Accepted Answer · edited May 08 '14 at 21:05

2

Rather than doing this...

else if (0 < warriors < 50) {
    cell.accessoryView = firstLevel;
    // NSLog(@"50");
}

do this...

else if (0 < warriors && warriors < 50) {
    cell.accessoryView = firstLevel;
    // NSLog(@"50");
}

EDIT

To answer your comment...you probably mean to have some <= or >= in there, as it's going to the last else when warriors equals the border of your if conditionals (50, 100 or 500).

You probably want it to look like this...

 NSInteger warriors = [entry.prayerWarriors intValue];

    if (warriors == 0) {
        //Do nothing
        //NSLog(@"0");
    }
    else if (0 < warriors && warriors <= 50) {
        cell.accessoryView = firstLevel;
        // NSLog(@"50");

    }
    else if (50 < warriors && warriors <= 100) {
        cell.accessoryView = secondLevel;
        //  NSLog(@"100");

    }
    else if (100 < warriors && warriors <= 500) {
        cell.accessoryView = thirdLevel;
        //   NSLog(@"500");

    }
    else {
        cell.accessoryView = fourthLevel;
        //   NSLog(@"A Lot");

    }

edited May 08 '14 at 21:05

user717452

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answered May 08 '14 at 20:32

martskins

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I have changed my code to `NSInteger warriors = [entry.prayerWarriors intValue]; if (warriors == 0) { } else if (0 < warriors && warriors < 50) { cell.accessoryView = firstLevel; } else if (51 < warriors && warriors < 100) { cell.accessoryView = secondLevel; } else if (101 < warriors && warriors < 500) { cell.accessoryView = thirdLevel; } else { cell.accessoryView = fourthLevel; } `But it doesn't see the 3rd or 4th ones. – user717452 May 08 '14 at 20:42
maybe your missing some <= or >= ? the way you have it there it's going to the else when warriors equals either 100, 50, 500 – martskins May 08 '14 at 20:44
You have breaks where nothing will be true every 50 warriors. E.g. if warriors is 50, then warriors < 50 and 51 < warriors are both false, so the default else at the end will be used. You probably want 50 <= warriors, etc. – David Berry May 08 '14 at 20:45
Please note that the first level has a range of 51 (0-50) while the other levels has a range of 50 (i. e. 51-100). Do you want that? – Amin Negm-Awad May 13 '14 at 05:20

score 1 · Answer 2 · answered May 08 '14 at 20:33

1

The statement

if (0 < warriors < 50)

evaluates different than you might think. The first part

(0 < warriors)

evaluates as a boolean, and that boolean will be compared to 50.

So, you need to do: if (0 < warriors && warriors < 50)

answered May 08 '14 at 20:33

augustzf

2,385
1
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score 0 · Answer 3 · answered May 08 '14 at 20:44

The other answers make good points about the later cases needing a logical and but if you are getting stuck at if (warriors == 0) { most likely your object entry.prayerWarriors is nil. Put a break point and print it out. (and print out it's class to make sure its as expected)

Also minor but a good habit to be in your conversion of what I'm guessing is an NSNumber isn't using the same type as your variable. Since you are writing into a NSInteger you should replace intValue with integerValue

score 0 · Answer 4 · answered May 08 '14 at 20:53

For clarity, I prefer to put the variable first in each condition and to encapsulate each part of the condition:

if (warriors == 0) {
 //Do nothing
NSLog(@"0");
}
else if ((warriors > 0) && (warriors < 50))
{
cell.accessoryView = firstLevel;
NSLog(@"50");
}
else if ((warriors > 51) && (warriors < 100)) {
 cell.accessoryView = secondLevel;
 NSLog(@"100");
    }
    else if ((warriors > 101) && (warriors < 500)) {
        cell.accessoryView = thirdLevel;
        NSLog(@"500");
    }
    else {
        cell.accessoryView = fourthLevel;
        NSLog(@"A Lot");
    }

Just be sure you've have enough parens around the conditions.

for clarity, you might want to double check how you indent your code! and all those double parenthesis are just way too much information for my eyes. Just a personal opinion though — martskins, May 08 '14 at 20:54

score 0 · Answer 5 · answered May 13 '14 at 05:29

You do not need an if cascade for this:

You can store the levels one time anywhere

NSArray *levels = @[firstLevel, secondLevel, thirdLevel, fourthLevel];

And use it indexed:

if( warriors > 0) {
  cell.accessoryView = levels[(warriors-1) / 50]
}

But if you want to have an if cascade, you do not have to double check:

NSInteger warriors = [entry.prayerWarriors intValue];

if (warriors == 0) {
    //Do nothing
    //NSLog(@"0");
}
else if (warriors <= 50) {
    cell.accessoryView = firstLevel;
    // NSLog(@"50");

}
else if (warriors <= 100) {
    cell.accessoryView = secondLevel;
    //  NSLog(@"100");

}
else if (warriors <= 500) {
    cell.accessoryView = thirdLevel;
    //   NSLog(@"500");

}
else {
    cell.accessoryView = fourthLevel;
    //   NSLog(@"A Lot");

}

If you are in an else, it is already tested that the preceding condition failed.(That's the meaning of else.)

Using multiple else if statements for NSInteger

5 Answers5