objective-c setter 2d-array

Hi,

i want to initialize a 2d array.. but my code doesn`t work,

can somebody tell me what is wrong?

Thanks Chris

@interface Map : NSObject {
    int mapData[8][8]; 
}
@property(readwrite) int** mapData;
@end


@implementation Map
@synthesize **mapData; (Error: Syntax before *)

- (id)initWithMap:(int[8][8])map {

    for (int i=0; i<8; i++) {
     for (int j=0; j<8; j++) {
      self.mapData[i][j] = map[i][j];
     }
    }
    return self;
}

@end

(Warning mapData requires method... use @synthesize or.......)

Edit: if i remove the type at synthesize as suggested, the compiler tells me another error:error type of property mapData does not match type of ivar mapData

Edit#2: can somebody please post the corrected code? i´m working at this really silly problem for over an hour.. (no c/c++ background, but java)

From stackoverflow

• The synthesize statement of a property does not need to specify the type, just the name.

  So;

  @synthesize mapData;
  

  Also because mapData is an instance variable you do not need to use the "self.mapData" syntax. You could just do;

  mapData[i][j] = map[i][j];
  

  Finally, realise that these are just blocks of data so you can copy everything in one go. E.g

  // could also be sizeof(mapData) but this is more instructive
  memcpy(mapData, map, sizeof(int) * 8 * 8);
  

  chrisx : okay, i now removed they type information.. now i get the error: error type of property mapData does not match type of ivar mapData

• also

  int mapData[8][8];
  

  and

  int **mapData;
  

  is interpreted differently. The first will be an array with 64 consecutive ints and the other a pointer to a pointer to an int.

  Maybe this can work for you, wrapping the 2d array in a struct...

  struct map_s {
    int map[8][8];
  };
  typedef struct map_s map_t;
  
  @interface Map : NSObject {
    map_t mapData;
  }
  @property (nonatomic, readwrite) map_t mapData;
  @end
  
  
  @implementation Map
  @synthesize mapData;
  
  - (id)initWithMap:(map_t)map {
    int i, j;
    for (i=0; i<8; i++) {
      for (j=0; j<8; j++) {
        self.mapData.map[i][j] = map.map[i][j];
      }
    }
    return self;
  }
  
  @end
  

  Rewritten a little to show a map initializer

  struct map_s {
    int map[8][8];
  };
  typedef struct map_s map_t;
  
  @interface Map : NSObject {
    map_t mapData;
  }
  @property (nonatomic, readwrite) map_t mapData;
  - (void)init;
  - (id)initWithMap:(map_t)map;
  @end
  
  
  @implementation Map
  @synthesize mapData;
  
  - (void)init
  {
    map_t first = {
      {
        { 0,0,0,0,0,0,0,0 },
        { 0,0,0,0,0,0,0,0 },
        { 0,0,0,0,0,0,0,0 },
        { 0,0,0,0,0,0,0,0 },
        { 0,0,0,0,0,0,0,0 },
        { 0,0,0,0,0,0,0,0 },
        { 0,0,0,0,0,0,0,0 },
        { 0,0,0,0,0,0,0,0 }
      }
    };
    [self initWithMap:first];
  }
  
  - (id)initWithMap:(map_t)map {
    mapData = map;
    return self;
  }
  
  @end
  

  chrisx : i think i want the first thing.. not the pointer vector.. what do i have to do to change id?

  chrisx : and how would i define a map_t int the code? map_t first = { {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0} } throws hundrets of errors :-(

  epatel : what does the errors say? any error prior? because that works fine here...

  chrisx : got it working now, i think it was some stupid syntax error :-). thanks a lot for your help! have a nice day :-)

• I don't think you can have properties of array types. Can you just use a getter/setter instead? For example:

  @interface Map : NSObject {
      int mapData[8][8];  
  }
  - (int)getI:(int)i j:(int)j;
  - (int)setI:(int)i j:(int)j to:(int)v;
  @end
  
  
  @implementation Map
  
  - (id)initWithMap:(int[8][8])map {
  
      for (int i=0; i<8; i++) {
          for (int j=0; j<8; j++) {
              mapData[i][j] = map[i][j];
          }
      }
      return self;
  }
  
  - (int)getI:(int)i j:(int)j {
      return mapData[i][j];
  }
  
  - (void)setI:(int)j j:(int)j toValue:(int)v {
      mapData[i][j] = v;
  }
  
  @end