very basic objective-c question - objective-c

Question

I wrote a simple program to understand how objective-c works. This program is the i-ching, an ancient divination based on six lines response, calculated after launching three coins for six times, and then build an hexagram which is the reponse.
I am stuck at this, that I am sure has simple solution. This is how I defined the lines, I know it's not the best design, but I am trying to use as much technology as possible.
Supposing you launch a coin, it can be 3 or 2 depending on the side, three coins result in possible value 6,7,8,9.
/**
* identifying a coin
*/
typedef enum {
head=3,
tail=2
} Coin;
/**
identify a line, three coins with a side value of
2 and 3 can result in 6,7,8,9
*/
typedef enum {
yinMutable=tail+tail+tail, // 6 --> 7
yang=tail+tail+head, // 7
yin=head+head+tail, // 8
yangMutable=head+head+head // 9 --> 8
} Line;
/**
The structure of hexagram from bottom "start" to top "end"
*/
typedef struct {
Line start;
Line officer;
Line transit;
Line minister;
Line lord;
Line end;
} Hexagram;
The first problem I encounter with this design is to assign a value at each line in Hexagram. The first launch should fill value in start, the second in officer....and so on.
But can be easily solved with a switch case...altough I don't like it.
1) First question: I wonder if there is some function like in javascript or c# like
foreach (property in Hexagram) that let me browse the properties in their declaration order, that would solve my problem.
2) Second question: as an alternative way I used an array of Line:
Controller.m
....
Line response[6]
....
-(id) buildHexagram:... {
for(i =0.....,i++).....
response[i]=throwCoins;
// I omit alloc view and the rest of the code...then
[myview buildSubview:response];
}
----------------------
subView.m
-(id) buildSubView:(Line[]) reponse {
NSLog(#"response[0]=%o",[response objectAtIndex[0]]); <--- HERE I GOT THE ERROR
}
but then, whit this solution I got an error EXC_BAD_ACCESS
So obviously I am misunderstanding how array works in objective-c or c !
In the hope I have made myself clear enough, can someone point out the solution to the first question, and what I am doing wrong in the second option.
thanks
Leonardo

Answer 1

You've created a C array of Line - to access the elements you need to use C style array accessors.
So instead of
[response objectAtIndex[0]]
use
response[0]