Unused variable warning in objective c

Question

I'm trying to learn objective-c and have encountered a warning in this example:

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])

{
    @autoreleasepool {

        NSMutableDictionary *booklisting = [NSMutableDictionary dictionary];

        int count; // < Am getting 'unused variable' warning here 

        [booklisting setObject:@"Wind in the Willows" forKey:@"100-432112"];
        [booklisting setObject:@"Tale of Two Cities" forKey:@"200-532874"];
        [booklisting setObject:@"Sense and Sensibility" forKey:@"200-546549"];

        [booklisting setObject:@"Shutter Island" forKey:@"104-109834"];


       NSLog(@"Number of books in dictionary = %lu", [booklisting count]);

would anyone know why?.. Would appreciate help..thanks

score 2 · Answer 1 · answered Jun 10 '13 at 07:59

2

you are not using any where in your code.that's why warning comes like this.

int count;// count is an variable  and
[booklisting count]//here count is a property of NSArray reference class

remove int count; and check it.

answered Jun 10 '13 at 07:59

+ 1, but `[booklisting count]` is in this case a method of `NSDictionary` ;) – HAS Jun 10 '13 at 09:59
yes Exactly for both aray and dictinary classes having the property count. – Jun 10 '13 at 10:00
Yeah, but monkeyboy is using an `NSMutableDictionary` and not an `NSArray` and so your comment `//here count is a property of NSArray reference class` is wrong in this case ;) – HAS Jun 10 '13 at 10:03
NSMutableArray is subclass to NSArray na. – Jun 10 '13 at 10:04
Of course it is, but we are not talking about `NSArray` at all, but **`NSDictionary`** (and **`NSMutableDictionary`**). – HAS Jun 10 '13 at 10:07
1

i agree with you regarding this question. – Jun 10 '13 at 10:09

score 1 · Answer 2 · answered Jun 10 '13 at 07:59

1

you arent using count... [booklisting count] is accessing a method of booklisting which is a NSMutableDictionary which has a method called count which returns how many entries are in the dictionary.

its coincidence that they have the same name.

answered Jun 10 '13 at 07:59

Fonix

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score 0 · Answer 3 · answered Jun 10 '13 at 08:01

0

put this line

count =[booklisting count];

before NSLog

or remove this int count; line

count is getter method for array.

answered Jun 10 '13 at 08:01

Ishu

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Thanks.. I commented out the int count line and it worked. I'm a bit confused though. The code that I used is exactly the same as instructed from an ebook called "Objective-C 2.0 Essentials" by Neil Smyth. I got it from techtopia.com – how could he be wrong? Or have I done something wrong? – monkeyboy Jun 10 '13 at 11:42

score 0 · Answer 4 · answered Jun 10 '13 at 08:19

0

Just remove int count; since you have not used variable count.

answered Jun 10 '13 at 08:19

Ayush

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score 0 · Answer 5 · answered Jun 10 '13 at 09:36

0

int count; // < Am getting 'unused variable' warning here

You declare a variable count.But it is never used.Hence the error is shown

answered Jun 10 '13 at 09:36

Lithu T.V

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Unused variable warning in objective c

5 Answers5