Category Files Dinner+CleanUp.h & Dinner+CleanUp.m for "An Introduction to Categories in Objective-C."

Dinner+CleanUp.h

// Dinner+CleanUp.h
#import "Dinner.h"
@interface Dinner (CleanUp)
  - (void)bringDishesToSink;
  - (NSUInteger)countTotalDishes;
  - (void)putDishesInDishwasher;
  - (void)removeDishesFromDishwasher;
@end

  
// Dinner+CleanUp.m
#import "Dinner+CleanUp.h"
@implementation Dinner (CleanUp)
  - (void)bringDishesToSink
  {
      //Do something to get dishes to sink.
  }
  - (NSUInteger)countTotalDishes
  {
      //Do something to count dishes.
  }
  - (void)putDishesInDishwasher
  {
      //Do something to put dishes in dishwasher.
  }
  - (void)removeDishesFromDishwasher
  {
      //Do something to put remove dishes from dishwasher.
  }
@end