Best way to declare an array of NSInteger in objective-c

Question

In the header file I want to declare an array of NSInterger, what's the best way to do that? I try this code, but it lead to an error

@interface test:NSObject
{
}
@property(nonatomic,readwrite)NSInteger f[4]={1,2,3,4}; // Error!!!
@end

you do not initialize a property in the header do it in the implementation file specifically in the `init` method — Joshua, Jan 20 '14 at 08:08

trojanfoe · Accepted Answer · 2014-01-20T08:34:37.320

You cannot do this; instead initialize the array in the object's init method and provide a custom setter/getter:

Header:

@interface test:NSObject
{
    NSInteger _f[4];
}
@property(nonatomic,readwrite) NSInteger *f;
@end

Implementation:

@implementation test

- (id)init {
    self = [super init];
    if (self) {
        _f[0] = 1;
        _f[1] = 2;
        _f[2] = 3;
        _f[3] = 4;
    }
    return self;
}

- (NSInteger *)f {
    return _f;
}

- (void)setF:(NSInteger *)f {
    for (NSUInteger i = 0; i < 4; i++)
        _f[i] = f[i];
}

@end

score 2 · Answer 2 · answered Jan 20 '14 at 08:18

2

Are you sure you want an array of NSIntegers? NSIntegers are a primitive type; they are not objects. The usual convention in Objective-C for most use cases would be to store an NSArray of NSNumber objects. A literal number can be converted into an NSNumber by prefixing it with the @ symbol.

In your header:

@property(nonatomic, strong) NSArray *myArray;

In your init method or similar:

self.myArray = @[ @1, @2, @3, @4 ];

answered Jan 20 '14 at 08:18

James Frost

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And how to get the values in this way? – Hazem Abdullah Jan 20 '14 at 08:47
1

To retrieve values, you can access elements like you would a normal C array: `NSNumber *number = self.myArray[0];`. Note that if you want a primitive `NSInteger` value back (rather than an `NSNumber` object), you'll need to call `integerValue` on the number: `[number integerValue];`. – James Frost Jan 20 '14 at 09:15

santhu · Answer 3 · 2014-01-20T08:35:10.743

0

int array[100]; create it as a global variable.

In your .m file add it after,

@interface MyClass ()

@end

@implementation MyClass{
}
int a[] ={1,2,34};

-(void)init{,.....

Try to NSLog(@"%d",a[1]), it will print perfectly.

edited Jan 20 '14 at 08:35

answered Jan 20 '14 at 08:05

santhu

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But I want to put some values directly to the array? int array[100]={1,2,3,4} lead to error too? – Hazem Abdullah Jan 20 '14 at 08:08
int array[]={1,2,3,4}. this way sir. – santhu Jan 20 '14 at 08:10
2

Sorry, but it's not working, my question in Objective-c ! – Hazem Abdullah Jan 20 '14 at 08:12
you can write c and c++code in objective C. updated the answer, try it once. – santhu Jan 20 '14 at 08:18
+1 for oldschool solution. I use it often by myself. – Cy-4AH Jan 20 '14 at 08:35
mee too, most of the algos if i need to use, i write them in c. – santhu Jan 20 '14 at 08:37

Best way to declare an array of NSInteger in objective-c

3 Answers3