#import <Cocoa/Cocoa.h>

@interface PolygonShape : NSObject 
{
 int numberOfSides, maximumNumberOfSides, minimumNumberOfSides;
}

@property (readwrite) int numberOfSides, maximumNumberOfSides, minimumNumberOfSides; 
@property (readonly) float angleInDegrees, angleInRadians;
@property (readonly) NSString * name; 
@property (readonly) NSString * description;
-(id) init;
-(void) setNumberOfSides:(int)sides;
-(void) setMinimumNumberOfSides:(int)min;
-(void) setMaximumNumberOfSides:(int)max;
-(float) angleInDegrees;
-(float) angleInRadians;
-(NSString *) name;
-(id) initWithNumberOfSides:(int) sides minimumNumberOfSides:(int) min maximumNumberOfSides:(int) max;
-(NSString *) description;
-(void) dealloc;
@end



#import "PolygonShape.h"

@implementation PolygonShape
-(id) init
{
 return [self initWithNumberOfSides:4 minimumNumberOfSides:3 maximumNumberOfSides:5];
}
@synthesize numberOfSides, minimumNumberOfSides, maximumNumberOfSides, angleInRadians;
-(void) setNumberOfSides:(int)sides
{
 numberOfSides = sides;
 NSLog(@"The number of sides is off limit so the number of sides is %@.",sides);
}
-(void)setMaximumNumberOfSides:(int)max
{
 if (maximumNumberOfSides <= 12) 
 {
  maximumNumberOfSides = max;
 }
}
-(void)setMinimumNumberOfSides: (int)min
{
 if (minimumNumberOfSides > 2) 
 {
  minimumNumberOfSides = min;
 }
}
- (id)initWithNumberOfSides:(int)sides minimumNumberOfSides:(int)min
    maximumNumberOfSides:(int)max
{
 if(self=[super init])
 {
  [self setNumberOfSides:(int)sides];
  [self setMaximumNumberOfSides:(int)max];
  [self setMinimumNumberOfSides: (int)min];
 }
 return self;
}
-(float) angleInDegrees
{
 float anglesInDegrees = (180 * (numberOfSides - 2) / numberOfSides);
 return anglesInDegrees;
}
-(float)angleInRadiants
{
 float anglesInRadiants = ((180 * (numberOfSides - 2) / numberOfSides) * (180 / M_PI));
 return anglesInRadiants;
}
-(NSString *)name
{
 NSString * output;
 switch (numberOfSides)
 {
  case 3:
   output = @"Triangle";
   break;
  case 4:
   output = @"Square";
   break;
  case 5:
   output = @"Pentagon";
   break;
  case 6:
   output = @"Hexagon";
   break;
  case 7:
   output = @"Heptagon";
   break;
  case 8:
   output = @"Octagon";
   break;
  case 9:
   output = @"Nonagon";
   break;
  case 10:
   output = @"Decagon";
   break;
  case 11:
   output = @"Hendecagon";
   break;
  case 12:
   output = @"Dodecabgon";
   break;
  default:
   output = @"Invalid number of sides: %i is greater than maximum of five allowed.";
 }
 return output;

}
-(NSString *)description
{
 NSString * output;
 NSLog(@"Hello I am a %i-sided polygon (aka a %@) with angles of %f degrees (%f radians).",
    numberOfSides, output, [self angleInDegrees], [self angleInRadiants]);
 return [self description];
}
-(void)dealloc
{
 [super dealloc];
}   

@end



#import <Foundation/Foundation.h>
#import "PolygonShape.h"

void PrintPathInfo()
{
 NSLog(@"Section 1");
 NSLog(@"--------------------");
 NSString  *path = [@"~" stringByExpandingTildeInPath];
 NSLog(@"My home folder is at '%@'.", path);
 NSArray *pathComponent = [path pathComponents];
 for (path in pathComponent)
 {
  NSLog(@"%@",path);
 }
 NSLog(@"--------------------");
 NSLog(@"\n");
}

void PrintProcessInfo()
{
 NSLog(@"Section 2");
 NSLog(@"--------------------");
 NSString * processName = [[NSProcessInfo processInfo] processName];
 int processIdentifier = [[NSProcessInfo processInfo] processIdentifier];
 NSLog(@"Process Name: '%@', Process ID: '%i'", processName, processIdentifier);
 NSLog(@"--------------------");
 NSLog(@"\n");
}

void PrintBookmarkInfo()
{
 NSLog(@"Section 3");
 NSLog(@"--------------------");
 NSArray * keys = [NSArray arrayWithObjects:
       @"Stanford University",
       @"Apple",
       @"CS193P",
       @"Stanford on iTunes U",
       @"Stanford Mall", nil];
 NSArray * objects = [NSArray arrayWithObjects:
       [NSURL URLWithString: @"http://www.stanford.edu"],
       @"http://www.apple.com",
       @"http://cs193p.stanford.edu",
       @"http://itunes.stanford.edu",
       @"http://stanfordshop.com",nil];
 NSMutableDictionary * dictionary = [NSMutableDictionary dictionaryWithObjects:objects forKeys:keys];
 NSEnumerator * enumerator = [keys objectEnumerator];
 for (id keys in dictionary)
 {
  NSLog(@"key: '%@', value: '%@'", keys, [dictionary objectForKey:keys]);
 }
 NSLog(@"                                                  ");
 NSLog(@"These are the ones that has the prefix 'Stanford'.");
 NSLog(@"                                                  ");
 id object;
 while (object = [enumerator nextObject]) 
 { 
  if ([object hasPrefix: @"Stanford"]) 
  {
   NSLog(@"key: '%@', value: '%@'", object, [dictionary objectForKey:object]);
  }
 }
 NSLog(@"--------------------");
 NSLog(@"\n"); 

}

void PrintIntrospectionInfo()
{
 NSLog(@"Section 4");
 NSLog(@"--------------------");
 SEL lowercase = @selector (lowercaseString);
 NSMutableArray * array = [NSMutableArray array];
 [array addObject: [NSString stringWithString: @"Here is a string"]];
 [array addObject: [NSDictionary dictionary]];
 [array addObject: [NSURL URLWithString: @"http://www.stanford.edu"]];
 [array addObject: [[NSProcessInfo processInfo]processName]];
 for (id keys in array)
 {
  NSLog(@"\n");
  NSLog(@"Class Name: %@", [keys className]);
  NSLog(@"Is Member of NSString: %@", [keys isMemberOfClass:[NSString class]]?@"Yes":@"No");
  NSLog(@"Is Kind of NSString: %@", [keys isKindOfClass:[NSString class]]?@"Yes":@"No");
  if ([keys respondsToSelector: lowercase]==YES) 
  {
   NSLog(@"Responds to lowercaseString: %@",[keys respondsToSelector: lowercase]?@"Yes":@"No");
   NSLog(@"lowercaseString is: %@", [keys performSelector: lowercase]);
  }
  else 
  {
   NSLog(@"Responds to lowercaseString: %@",[keys respondsToSelector: lowercase]?@"Yes":@"No" );
  }
 }
 NSLog(@"--------------------");
}
void PrintPolygonInfo()
{
 NSMutableArray * array = [NSMutableArray array];
 PolygonShape * polygon1 = [[PolygonShape alloc]initWithNumberOfSides:4 minimumNumberOfSides:3 maximumNumberOfSides:7];
 [array addObject:polygon1];
 [array description];
 PolygonShape * polygon2 = [[PolygonShape alloc]initWithNumberOfSides:6 minimumNumberOfSides:5 maximumNumberOfSides:9];
 [array addObject:polygon2];
 [array description];
 PolygonShape * polygon3 = [[PolygonShape alloc]initWithNumberOfSides:12 minimumNumberOfSides:9 maximumNumberOfSides:12];
 [array addObject:polygon3];
 [array description];

 [array release];
 [polygon1 release];
 [polygon2 release];
 [polygon3 release];
}


int main (int argc, const char * argv[]) 
{
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

 PrintPathInfo();
 PrintProcessInfo();
 PrintBookmarkInfo();
 PrintIntrospectionInfo();
 PrintPolygonInfo();

    [pool release];
    return 0;
}

//The result was "EXC_BAD_ACCESS", but I couldn't figure out how to resolve this problem.