March 2014 update

Task/Anonymous-recursion/Objective-C/anonymous-recursion-1.m

@@ -15,19 +15,18 @@
   if (i < 2)
     result = 1;
   else
-    result = [[self performSelector:_cmd withObject:[NSNumber numberWithInt:i-1]] intValue]
-           + [[self performSelector:_cmd withObject:[NSNumber numberWithInt:i-2]] intValue];
-  return [NSNumber numberWithInt:result];
+    result = [[self performSelector:_cmd withObject:@(i-1)] intValue]
+           + [[self performSelector:_cmd withObject:@(i-2)] intValue];
+  return @(result);
 }
 @end
 
 int main (int argc, const char *argv[]) {
-  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+  @autoreleasepool {
 
-  AnonymousRecursion *dummy = [[AnonymousRecursion alloc] init];
-  NSLog(@"%@", [dummy fibonacci:[NSNumber numberWithInt:8]]);
-  [dummy release];
+    AnonymousRecursion *dummy = [[AnonymousRecursion alloc] init];
+    NSLog(@"%@", [dummy fibonacci:@8]);
 
-  [pool release];
+  }
   return 0;
 }

Task/Anonymous-recursion/Objective-C/anonymous-recursion-2.m

@@ -5,21 +5,22 @@ int fib(int n) {
         @throw [NSException exceptionWithName:NSInvalidArgumentException
                                  reason:@"fib: no negative numbers"
                                userInfo:nil];
-    __block int (^f)(int);
-    f = ^(int n) {
+    int (^f)(int);
+    __block __weak int (^weak_f)(int); // block cannot capture strong reference to itself
+    weak_f = f = ^(int n) {
         if (n < 2)
             return 1;
         else
-            return f(n-1) + f(n-2);
+            return weak_f(n-1) + weak_f(n-2);
     };
     return f(n);
 }
 
 int main (int argc, const char *argv[]) {
-  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+  @autoreleasepool {
 
-  NSLog(@"%d", fib(8));
+    NSLog(@"%d", fib(8));
 
-  [pool release];
+  }
   return 0;
 }

Task/Anonymous-recursion/Objective-C/anonymous-recursion-3.m

@@ -0,0 +1,25 @@
+#import <Foundation/Foundation.h>
+
+int fib(int n) {
+    if (n < 0)
+        @throw [NSException exceptionWithName:NSInvalidArgumentException
+                                 reason:@"fib: no negative numbers"
+                               userInfo:nil];
+    __block int (^f)(int);
+    f = ^(int n) {
+        if (n < 2)
+            return 1;
+        else
+            return f(n-1) + f(n-2);
+    };
+    return f(n);
+}
+
+int main (int argc, const char *argv[]) {
+  @autoreleasepool {
+
+    NSLog(@"%d", fib(8));
+
+  }
+  return 0;
+}