wleofeng / iOShopping-Cart-001

Shopping Cart

Objectives

1. Create a custom class file that inherits from NSObject.
2. Import another custom class.
3. Declare a property on a custom class.
4. Write methods for the custom class to perform on a property that it owns.

Instructions

Open the iOShoppingCart.xcworkspace file. You should see the familiar FISAppDelegate class and a FISItem class set up already.

I. Create a new FISShoppingCart class the inherits from NSObject.
Import FISItem into FISShoppingCart's header file.
Declare one property, an NSMutableArray called items.
Declare the following 11 methods in FISShoppingCart.h:

• calculateTotalPriceInCents which takes no arguments and returns an NSUInteger,
• addItem: which takes one FISItem argument called item and provides no return,
• removeItem: which takes one FISItem argument called item and provides no return,
• removeAllItemsLikeItem: which takes on FISItem argument called item and provides no return,
• sortItemsByNameAsc which takes no arguments and provides no return,
• sortItemsByNameDesc which takes no arguments and provides no return,
• sortItemsByPriceInCentsAsc which takes no arguments and provides no return,
• sortItemsByPriceInCentsDesc which takes no arguments and provides no return,
• allItemsWithName: which takes one NSString argument called name and returns an NSArray,
• allItemsWithMinimumPriceInCents: which takes one NSUInteger argument and returns an NSArray, and
• allItemsWithMaximumPriceInCents: which takes one NSUInteger argument and returns an NSArray.

Define the initial method implementations in FISShoppingCart.m to either:

• return nil for methods that provide a return, or
• do nothing for methods that do not provide a return.

Run the tests with ⌘ U to check that the tests in FISShoppingCartSpec.m initially fail.

II. Complete each of the method implementations so that they pass their tests:

1. calculateTotalPriceInCents should calculate the sum of the priceInCents property of all the items in the items array. Naturally, this should return 0 if the items array is empty.

2. addItem: should add the submitted item to the items array, even if the item is already in the items array (sometimes you just need to stock up on hot pockets!).

3. removeItem: should remove a single occurrence of an item in the items array.
   Hint: Use NSMutableArray's indexOfObject: andremoveObjectAtIndex: method.

4. removeAllItemsLikeItem: should remove all occurrences of an item in the items array.

5. sortItemsByNameAsc should sort the contents of the items array by their name property in ascending order (alphabetical).
   Hint: Use NSSortDescriptor for these methods.

6. sortItemsByNameDesc should sort the contents of the items array by their name property in descending order.

7. sortItemsByPriceInCentsAsc should sort the contents of the items array by the priceInCents property in ascending order.

8. sortItemsByPriceInCentsDesc should sort the the contents of the items array by the priceInCents property in descending order.

9. allItemsWithName: should return an array containing only the items whose name property matches the argument string.
   Hint: Use NSPredicate for these methods.

10. allItemsWithMinimumPriceInCents: should return an array containing only the items whose priceInCents property is greater than or equal to the argument integer.

11. allItemsWithMaximumPriceInCents: should return an array containing only those items whose priceInCents property is less than or equal to the argument integer.