Objective C Demo

objc.m

/****** ObjC.h ******/

#import <somelib.h>

@class MyClass; // forward declaration

// a protocol is similar to an abstract class in C++
@protocol MyProtocol 
- (BOOL) protocolFunction;
@end

// Objective C does not have templates. The class between the arrows below just declares what protocol it impliments.
// Note that an object can inhereit only one base class but multiple protocols.
// NSObject is the base class of all objects in objective c

@interface MyClass : NSObject<MyProtocol> {
   int _protected_value;          // member values are protected by default
   void(^_callback)(float val);   // function pointer.
   @public
   int _public_value;             // public variable
}

// properties are variables that automatically create getters and setters for you. You can override them if needed.
// options between in brackets here define behaviour of the property. 
// For instance, nonatomic means the property can be accessed by multiple threads are the same time.
@property (nonatomic, readonly) NSString* PropertyString;

+ (MyClass *)sharedInstance;     // static function.

- (instancetype)init;            // constructor
- (void)dealloc;                 // destructor

- (void)classFunction:(NSString*)name callback:(void(^)(float))callback;

@end

/****** ObjC.m ******/

static MyClass* instance = nil;

@implementation MyClass

// you can change the internal variable name of properties using synthesize. 
// By default all properties get an underscore at the start of their name. 
@synthesize PropertyString = _property_string;

+ (MyClass*)sharedInstance
{
   if (instance == nil) {
      instance = [[self alloc] init];
   }
   return instance;
}

// constructor
- (instancetype)init
{
   self = [super init];
 
    if (self) {
        _protected_value = 1;
        _public_value = 2;
    }
 
    return self;
}

// destructor
- (void) dealloc
{
}

- (void)classFunction:(NSString*)name callback:(void(^)(float))callback
{
   _callback = callback;
}

- (BOOL) protocolFunction
{
    BOOL val = TRUE;
    return val;
}

@end

/****** main.m ******/

int main(int argc, const char * argv[])
{
    MyClass* test = [MyClass sharedInstance];
    NSString* str = @"some text";
    [test classFunction:str callback:^(float aFloat) { //lambda function
        // do something
    }];
}