Write a complex array of custom structs to file Objective C - objective-c

Question

I need to save and load the contents of an array of structs, but I know that Objective C is very particular about which data types you can read/write with.
Here is my struct:
struct SCourse
{
NSMutableArray* holes; // holds integers (pars)
NSString* name;
int size;
BOOL inUse;
};
#interface CoursesManager : NSObject
{
struct SCourse courses[5];
}
What are the data types I'll need to use? Do they each have different methods needed in order to read/write? I'm just looking for a non-complex way to get all the data I need to and from a file. I could do this quite easily in a language I'm more familiar with (C++), but some of the particulars of Objective-c are still lost on me.
EDIT: Solution (thanks for the help, everyone)
-(void)applicationWillResignActive:(UIApplication *)application {
// save the courses
NSMutableArray* totalWriteArray = [[NSMutableArray alloc] initWithCapacity:MAX_COURSES];
for (int i = 0; i < MAX_COURSES; ++i)
{
struct SCourse saveCourse = [coursesManager GetCourseAtIndex:i];
NSNumber* nInUse = [NSNumber numberWithBool:saveCourse.inUse];
NSNumber* nSize = [NSNumber numberWithInt:saveCourse.size];
NSMutableArray* writeArray = [[NSMutableArray alloc] initWithCapacity:4];
[writeArray addObject:nInUse];
[writeArray addObject:nSize];
[writeArray addObject:saveCourse.name];
[writeArray addObject:saveCourse.holes];
[totalWriteArray addObject:writeArray];
}
[totalWriteArray writeToFile:[self saveFilePath] atomically:YES];
}
And for the loading back in...
-(void)loadFile {
NSString *myPath = [self saveFilePath];
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:myPath];
if (fileExists) {
NSMutableArray* totalReadArray = [[NSMutableArray alloc] initWithContentsOfFile:[self saveFilePath]];
for (int i = 0; i < MAX_COURSES; ++i)
{
struct SCourse loadCourse = [coursesManager GetCourseAtIndex:i];
NSMutableArray* loadArray = [totalReadArray objectAtIndex:i];
NSNumber* nInUse = [loadArray objectAtIndex:0];
loadCourse.inUse = [nInUse boolValue];
NSNumber* nSize = [loadArray objectAtIndex:1];
loadCourse.size = [nSize integerValue];
NSString* inName = [loadArray objectAtIndex:2];
loadCourse.name = inName;
NSMutableArray* inHoles = [loadArray objectAtIndex:3];
loadCourse.holes = inHoles;
[coursesManager ReplaceCourseAtIndex:i With:loadCourse];
}
}
}

Answer 1

First thing first. You shouldn't use plain old C structures. The ARC memory management will not appreciate.
If you are familiar with C++, you should maybe use a C++ class instead, which will please the compiler and runtime. Depends on what you want to do.
Array. Use either NSArray or std::vector but please, no plain C arrays. Not sure how ARC will handle this but I suppose it will not appreciate much. Objective-C and C++ both provides all the tools you need to handle collections of whatever.
Serialization. You have several possibilities, one of them is NSCoder.
Last word, with the so called modern syntax, converting things into ObjC objects is quite easy.
BOOL b = YES;
int i = 10;
double d = 3.14;
char* s = "Pouf pouf";
You get the ObjC equivalents with the boxin' thingy:
NSNumber* bo = #( b );
NSNumber* io = #( i );
NSNumber* do = #( d );
NSString* so = #( s );
NSArray* ao = #[ #( i ), do ];
NSDictionary* = #{ #"num" : io, #"str" : #( s ) };
To write something in a file, in one gracious step:
[#{ #"bool" : bo, #"array" : #[ #"string", #10, #( 10 + 20 ) ] }
writeToFile: #"path.plist" atomically: YES];
But the question remains, what are you trying to accomplish?

Answer 2

One easy approach is to store these arrays in an NSMutableDictionary object and use the method:
[mutableDict writeToFile:#"path/to/file" atomically:YES];
To store the data and:
NSMutableDictionary *anotherDict = [NSMutableDictionary dictionaryWithContentsOfFile:#"path/to/file"];
To read the contents back in.

Answer 3

Here's what I'd suggest:
Make a custom class with the properties you want (.h file):
#import <Foundation/Foundation.h>
#interface CustomHolder : NSObject {
NSString *last;
NSString *first;
NSString *middle;
}
#property (strong, nonatomic) NSString *last;
#property (strong, nonatomic) NSString *first;
#property (strong, nonatomic) NSString *middle;
#end
And then set the .m file up so that you can encode/decode the object
#import "CustomHolder.h"
#implementation CustomHolder
#synthesize last, first, middle;
- (void)encodeWithCoder:(NSCoder *)encoder
{
[encoder encodeObject:first forKey:#"first"];
[encoder encodeObject:last forKey:#"last"];
[encoder encodeObject:middle forKey:#"middle"];
}
- (id)initWithCoder:(NSCoder *)decoder
{
if (self = [super init])
{
self.first = [decoder decodeObjectForKey:#"first"];
self.last = [decoder decodeObjectForKey:#"last"];
self.middle = [decoder decodeObjectForKey:#"middle"];
}
return self;
}
#end
Then you can just
[NSKeyedArchiver archiveRootObject:obj toFile:[self saveFilePath]] to save and
[NSKeyedUnarchiver unarchiveObjectWithFile:[self saveFilePath]] to load
That's probably the most similar to using C-structs (especially because ARC doesn't let you use structs).