Different approach to 4.10

[tomtso]

I did it differently.
 Instead of writing new methods , I made a memory instance (object), and reused the methods

Calculator *memory=[Calculator new];


   [memory setAccumulator: 100.0];                           //memoryStore
   NSLog(@"memory is %g",[memory accumulator]);   //memoryRecall 
   NSLog(@"memory is %g",[memory add:200]);         //memoryAdd
   NSLog(@"memory is %g",[memory subtract:10]);     //memorySubtract
   NSLog(@"memory is %g",[memory clear]);               //memoryClear

Is this lazy and not doing the excercise correctly?

At least it saved me a lot of line reproduction.