Objective-C簡易計算機

// Implement a Calculator class
#import <Foundation/Foundation.h>

@interface Calculator: NSObject {
  double accumulator;
}

// accumulator methods
-(void) setAccumulator: (double) value;
-(void) clear;
-(vdouble) accumulator;

// arithmetic methods
-(void) add: (double) value;
-(void) subtract: (double) value;
-(void) multiply: (double) value;
-(void) divide: (double) value;
@end

@implementation Calculator
-(void) setAccumulator: (double) value {
  accumulator = value;
}
-(void) clear {
  accumulator = 0;
}
-(void) accumulator {
  return accumulator;
}
-(void) add: (double) value {
  accumulator += value;
}
-(void) subtract: (double) value {
  accumulator -= value;
}
-(void) multiply: (double) value {
  accumulator *= value;
}
-(void) divide: (double) value {
  accumulator /= value;
}
@end

int main (int argc, const char *argv[]) {
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  Calculator *deskCalc;
  
  deskCalc = [[Calculator alloc] init];
  
  [deskCalc clear];
  [deskCalc setAccumulator: 100.0];
  [deskCalc add: 200.];
  [deskCalc divide: 15.0];
  [deskCalc subtract: 10.0];
  [deskCalc multipl: 5];
  NSLog (@"The result is %g", [deskCalc accumulator]);
  [deskCalc release];
  
  [pool drain];
  return 0;
}