CODEWITHSUNDEEP
objective-c
VenDiaS
VenDiaS

Reputation: 81

Objective C...Define structures?

I am new programming and Objective-C in general. Do I declare a struct in the interface and define it in the implementation use a void method ?...

@interface Elements : NSObject {


struct elementZ{

    NSString *name;
    float molarmass;

}elements[81];

Now that I have declared it..where do I initialize the elements[81] array?

Upvotes: 0

Views: 4598

Answers (4)

Mahesh
Mahesh

Reputation: 34655

Do I declare a struct in the interface and define it in the implementation use a void method ?

Yes it is what you think since Objective C is a super set of C. Have a method, that takes no arguments and returns void and initialize the member variables of struct elementz through elements[81];. Probably by running a loop from 0 to 80. As an example -

#import <Foundation/NSObject.h>

@interface Fraction: NSObject {
    struct myStructure {
        int numerator, denominatior;
    }objects[10];
}

-(void) print;
-(void) initialize;
@end

@implementation Fraction

-(void) initialize
{
    for( int i=0; i<10; ++i )
    {
        objects[i].numerator = (i+1);
        objects[i].denominatior = (i+2);
    }
}
-(void) print
{
    for( int i=0; i<10; ++i )
    {
        printf("%d\t%d\n", objects[i].numerator, objects[i].denominatior);
    }
}
@end

int main(int argc, char *argv[])
{
    Fraction *obj = [[Fraction alloc] init];    
    [ obj initialize ];
    [ obj print ];

    [ obj release ];
    return 0;
}

Output:

[Switching to process 949]
Running…
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11

Debugger stopped. Program exited with status value:0.

Hope it helps !

Upvotes: 1

Kai
Kai

Reputation: 511

Add a init method within the implementation block of your Elements class:

- (id)init {

    if (self = [super init]) {

        for (int i=0; i<81; i++) {
            elements[i].name = "foo";
        }
    }

    return self;
}

maybe some reading is required to get familar to Objective-C: Introduction to The Objective-C Programming Language

Object creation in Objective-C requires two steps:

  • Allocation
  • Initialization

E.g.:

Elements *e = [[Elements alloc] init];

Upvotes: 0

jakeva
jakeva

Reputation: 2835

Your code works as is for me. Then you can access the data in your implementation like so:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
    // Insert code here to initialize your application 
    elements[2].name = @"hello";
    NSLog(elements[2].name);
}

This will print 'hello' to the console.

Upvotes: 1

Micha&#235;l
Micha&#235;l

Reputation: 6734

typedef struct element{

    NSString *name;
    float molarmass;

}elementZ;

elementZ[81] array;

Upvotes: 0

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