Objective-C Chapter 4.5

// 4.5 연습문제 8번, 9번, 10번

#import <Foundation/Foundation.h>

@interface Calculator : NSObject

// 누산기 매서드

-(void) setAccumulator : (double) value;
-(void) clear;
-(double) accumulator;

// 산술 연산 매서드

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

// 연습문제 9번 추가 메서드

-(double) changeSign;  // 누산기의 부호를 바꿈
-(double) reciprocal;  // 1 / 누산기
-(double) xSquared;    // 누산기를 제곱

// 연습문제 10번 추가 메서드

-(double) memoryClear;  // 메모리를 저장한다

-(double) memoryStore;  // 누산기 값을 메모리에 설정한다

-(double) memoryRecall;  // 메모리 값을 누산기에 설정한다
-(double) memoryAdd : (double) value;  // 메모리에 value를 더한다
-(double) memorySubtract : (double) value;  // value를 메모리에서 뺀다

@end

@implementation Calculator

{
    double accumulator, memory; // memory 연습문제 10번 추가 변수
}
-(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;

}

// 연습문제 9번

-(double) changeSign
{

    return accumulator = - accumulator;

}
-(double) reciprocal
{

    return accumulator = 1.0 / accumulator;

}
-(double) xSquared
{

    return accumulator *= accumulator;

}

// 연습문제 10번

-(double) memoryClear
{
    return memory = 0;
}
-(double) memoryStore
{

    return memory = accumulator;

}
-(double) memoryRecall
{

    accumulator = memory;

    return memory; // 주의! 반환값은 메모리!

}
-(double) memoryAdd : (double) value
{
    return memory += value;
}
-(double) memorySubtract : (double) value
{
    return memory -= value;
}

@end

int main (int argc, char *argv[])
{

    @autoreleasepool {

        Calculator *deskCalc = [[Calculator alloc] init];
        [deskCalc setAccumulator : 100.0];

        NSLog(@"The setAccumulator result is %g", [deskCalc accumulator]);

        [deskCalc add : 200.0];
        NSLog(@"The add result is %g", [deskCalc accumulator]);
        [deskCalc divide : 15.0];

        NSLog(@"The divide result is %g", [deskCalc accumulator]);

        [deskCalc subtract : 10.0];

        NSLog(@"The subtract result is %g", [deskCalc accumulator]);

        [deskCalc multiply : 5];

        NSLog(@"The multiply result is %g", [deskCalc accumulator]);

        

        [deskCalc clear];

        // 연습문제 9번

        [deskCalc setAccumulator : -0.2];
        [deskCalc changeSign];

        NSLog(@"changeSign method makes accumulator %g", [deskCalc accumulator]);

        [deskCalc reciprocal];

        NSLog(@"reciprocal method makes accumulator %g", [deskCalc accumulator]);

        [deskCalc xSquared];

        NSLog(@"xSquared method makes accumulator %g", [deskCalc accumulator]);

        

        [deskCalc clear];

        // 연습문제 10번

        [deskCalc setAccumulator : 10];

        NSLog(@"[deskCalc setAccumulator : 10] method > accumulator : %g, memory : %g", [deskCalc accumulator], [deskCalc memoryClear]);

        NSLog(@"[deskCalc memoryStore] method > accumulator : %g, memory : %g", [deskCalc accumulator], [deskCalc memoryStore]);

        NSLog(@"[deskCalc memoryAdd : 5] method > accumulator : %g, memory : %g", [deskCalc accumulator], [deskCalc memoryAdd : 5]);

        NSLog(@"[deskCalc memorySubtract : 2] method > accumulator : %g, memory : %g", [deskCalc accumulator], [deskCalc memorySubtract : 2]);

        [deskCalc memoryRecall];  // memoryRecall 메서드기 때문에 미리 리콜을 해줘서 accumulator 를 변환해주고 표시해야함.

        NSLog(@"[deskCalc memoryRecall] method > accumulator : %g, memory : %g", [deskCalc accumulator], [deskCalc memoryRecall]);

    }
    return 0;
}