calculatorViewController.m
1 #import "CalculatorViewController.h" 2 #import "CalculatorBrain.h" 3 4 @interface CalculatorViewController ()//create private varible 5 @property (nonatomic) BOOL useIsInTheMiddleOfEnteringANumber; 6 7 @property (nonatomic, strong) CalculatorBrain *brain; 8 @end 9 10 @implementation CalculatorViewController11 12 @synthesize display = _display;13 @synthesize useIsInTheMiddleOfEnteringANumber = _useIsInTheMiddleOfEnteringANumber;14 @synthesize brain = _brain;15 16 - (CalculatorBrain *)brain //setter17 {18 if(!_brain) _brain = [[CalculatorBrain alloc] init];19 return _brain;20 }21 22 23 - (IBAction)digitPressed:(UIButton *)sender24 {25 NSString *digit = sender.currentTitle;26 if(self.useIsInTheMiddleOfEnteringANumber) {27 self.display.text = [self.display.text stringByAppendingString:digit]; 28 } else {29 self.display.text = digit;30 self.useIsInTheMiddleOfEnteringANumber = YES;31 }32 33 34 /*35 UILabel *myDisplay = self.display; //[self display]; getter36 NSString *CurrentText = [myDisplay text];37 NSString *newText = [CurrentText stringByAppendingString:digit];38 myDisplay.text = newText;//[myDisplay setText:newText]; setter39 */40 41 42 43 }44 45 - (IBAction)doublePressed:(UIButton *)sender {46 47 double result = [self.brain performOperation:sender.currentTitle];48 NSString *resultString = [NSString stringWithFormat:@"%g", result];49 self.display.text = resultString;50 }51 52 - (IBAction)operationPressed:(UIButton *)sender 53 {54 55 if(self.useIsInTheMiddleOfEnteringANumber) [self enterPressed];56 double result = [self.brain performOperation:sender.currentTitle];57 NSString *resultString = [NSString stringWithFormat:@"%g", result];58 self.display.text = resultString;59 60 }61 62 - (IBAction)enterPressed63 {64 [self.brain pushOperand:[self.display.text doubleValue]];65 self.useIsInTheMiddleOfEnteringANumber = NO;66 }67 68 69 @end viewController.h
1 #import2 3 @interface CalculatorViewController : UIViewController4 5 @property (weak, nonatomic) IBOutlet UILabel *display;6 7 @end
Brain.h
1 #import2 3 @interface CalculatorBrain : NSObject// model 4 5 6 - (void)pushOperand: (double)operand; 7 8 - (double) performOperation:(NSString *)operation; 9 10 @end
Brain.m
1 #import "CalculatorBrain.h" 2 @interface CalculatorBrain() 3 @property (nonatomic, strong) NSMutableArray *operandStack; 4 @end 5 6 7 @implementation CalculatorBrain 8 9 10 @synthesize operandStack = _operandStack;11 12 - (NSMutableArray *)operandStack//getter13 {14 if(_operandStack == nil) _operandStack = [[NSMutableArray alloc] init];15 return _operandStack;16 }17 18 19 - (void)pushOperand: (double)operand20 {21 22 [self.operandStack addObject:[NSNumber numberWithDouble:operand]];//must add double23 24 }25 26 - (double) popOperand27 {28 NSNumber *operandObject = [self.operandStack lastObject];29 if(operandObject != nil) [self.operandStack removeLastObject];30 return [operandObject doubleValue];31 }32 33 - (double) performOperation:(NSString *)operation34 {35 double result = 0;36 if([operation isEqualToString:@"+"]) {37 result = [self popOperand] + [self popOperand];38 } else if ([@"*" isEqualToString:operation]) {39 result = [self popOperand] * [self popOperand];40 } else if ([@"^" isEqualToString:operation]) {41 double d = [self popOperand];42 result = d * d;43 }44 [self pushOperand:result];45 return result;46 }47 48 @end
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