My Exercise 4.9

[Shawn McBee]

Here's 4.9 from me... The only thing I'm confused about is whether my reciprocal should show in the NSLog output as a fraction, because I could only figure out how to have it output as a decimal (while retaining it's usefulness in a calculator app).
NOTE: I am using 4.2 with ARC.

Thoughts and comments are appreciated.

Code: (Objective-C)

//

//

#import <Foundation/Foundation.h>

// ----- Implement a Calculator Class -----

@interface Calculator : NSObject 
{
@private
    double accumulator;
}

// ----- Accumulator Methods -----

-(void) setAccumulator: (double) value;
-(void) clear;
-(double) accumulator;
-(double) changeSign;       // Change sign of accumulator
-(double) reciprocal;       // Creates reciprocal of accumulator
-(double) xSquared;          // Squares accumulator

// ----- Arithmetic Methods -----

-(double) add: (double) value;
-(double) subtract: (double) value;
-(double) multiply: (double) value;
-(double) divide: (double) value;

@end

@implementation Calculator

-(void) setAccumulator:(double)value 
{
    accumulator = value;
}

-(void) clear
{
    accumulator = 0;
}

-(double) accumulator
{
    return accumulator;
}

-(double) add:(double)value
{
    accumulator += value;
    return accumulator;
}

-(double) subtract:(double)value
{
    accumulator -= value;
    return accumulator;
}

-(double) multiply:(double)value
{
    accumulator *= value;
    return accumulator;
}

-(double) divide: (double)value
{
    accumulator /= value;
    return accumulator;
}

-(double) changeSign
{
    return accumulator *= -1;
}

-(double) reciprocal
  {
      return accumulator = 1/accumulator;
  }

-(double) xSquared
{
    return accumulator *= accumulator;
}

@end

int main (int argc, const char * argv[])
{
    
    @autoreleasepool {
        
        Calculator *deskCalc = [[Calculator alloc] init];
        
        [deskCalc setAccumulator: 3.0];
        NSLog (@"We start with the number %g", [deskCalc accumulator]);
        [deskCalc changeSign];
        NSLog (@"If we change the sign, it becomes %g", [deskCalc accumulator]);
        [deskCalc changeSign];
        NSLog (@"Now we'll change it back to %g", [deskCalc accumulator]);
        [deskCalc xSquared];
        NSLog (@"If we square the number, we get %g", [deskCalc accumulator]);
        [deskCalc reciprocal];
        NSLog (@"And the reciprocal of our new number is %g, in decimal form", [deskCalc accumulator]);
        
        
        
    }
    return 0;
}