@protocol RealNumber
- (double)realValue;
@end
#import <Foundation/NSArray.h>
#import "RealNumber.h"
@interface NSMutableArray (RealArray)
- (void)addRealNumber:(id <RealNumber>)number;
- (void)sort;
@end
#import "RealArray.h"
@implementation NSMutableArray (RealArray)
- (void)addRealNumber:(id <RealNumber>)number {
[self addObject:number];
}
static NSInteger compareReal(id <RealNumber>a, id <RealNumber>b, void *_) {
double v = [a realValue] - [b realValue];
if (v > 0.0) return NSOrderedDescending;
if (v < 0.0) return NSOrderedAscending;
return NSOrderedSame;
}
- (void)sort {
[self sortUsingFunction:compareReal context:0];
}
@end
#import <Foundation/NSObject.h>
#import "RealNumber.h"
@class NSString;
@interface Fraction : NSObject <RealNumber>
{
int sgn; // sign
int num; // numerator
int den; // denominator
}
+ (id)fractionWithNumerator:(int)n denominator:(int)d;
- (id)initWithNumerator:(int)n denominator:(int)d;
- (Fraction *)add:(Fraction *)obj;
- (Fraction *)sub:(Fraction *)obj;
- (Fraction *)mul:(Fraction *)obj;
- (Fraction *)div:(Fraction *)obj;
- (NSString *)description;
@end
#import "Fraction.h"
#import <Foundation/NSString.h>
#import <stdlib.h>
#import <float.h>
@implementation Fraction
static int gcd(int a, int b) // Greatest Common Divisor
{
if (a < b)
return gcd(b, a);
if (b == 0)
return a;
return gcd(b, a % b);
}
/* Local Method */
- (void)reduce
{
int d;
if (num == 0) {
sgn = 1;
den = 1;
return;
}
if (den == 0) { // infinity
num = 1;
return;
}
if ((d = gcd(num, den)) == 1)
return;
num /= d;
den /= d;
}
/* make a temporary instance */
+ (id)fractionWithNumerator:(int)n denominator:(int)d
{
return [[self alloc] initWithNumerator:n denominator:d] ;
}
#define SIGN(a) ( ((a) >= 0) ? 1 : (-1) )
/* Designated Initializer */
- (id)initWithNumerator:(int)n denominator:(int)d
{
if ((self = [super init]) != nil) {
sgn = SIGN(n) * SIGN(d);
num = abs(n);
den = abs(d);
[self reduce];
}
return self;
}
- (Fraction *)add:(Fraction *)obj
{
int n, d;
if (den == obj->den) {
n = sgn * num + obj->sgn * obj->num;
d = den;
}else {
n = sgn * num * obj->den + obj->sgn * obj->num * den;
d = den * obj->den;
}
return [Fraction fractionWithNumerator:n denominator:d];
}
- (Fraction *)sub:(Fraction *)obj
{
Fraction *tmp;
tmp = [Fraction fractionWithNumerator: -1 * obj->sgn * obj->num
denominator: obj->den];
return [self add: tmp];
}
- (Fraction *)mul:(Fraction *)obj
{
int n = sgn * obj->sgn * num * obj->num;
int d = den * obj->den;
return [Fraction fractionWithNumerator:n denominator:d];
}
- (Fraction *)div:(Fraction *)obj
{
int n = sgn * obj->sgn * num * obj->den;
int d = den * obj->num;
return [Fraction fractionWithNumerator:n denominator:d];
}
- (NSString *)description
{
int n = (sgn >= 0) ? num : -num;
return (den == 1)
? [NSString stringWithFormat:@"%d", n]
: [NSString stringWithFormat:@"%d/%d", n, den];
}
/*protocol implemented*/
- (double)realValue {
if (den == 0) return DBL_MAX;
return (double)(sgn * num) / (double)den;
}
@end
#import <Foundation/NSString.h>
#import "RealNumber.h"
@interface NSString (Real) <RealNumber>
@end
#import "NSStringReal.h"
@implementation NSString (Real)
- (double)realValue {
return [self doubleValue];
}
@end
#import <Foundation/Foundation.h>
#import <stdio.h>
#import "RealNumber.h"
#import "Fraction.h"
#import "NSStringReal.h"
#import "RealArray.h"
int main(void) {
@autoreleasepool {
id array = [NSMutableArray array];
[array addRealNumber:@"1.3"];
[array addRealNumber:@"0.35"];
[array addRealNumber:@"0.2"];
[array addRealNumber:[Fraction fractionWithNumerator:1 denominator:3] ];
[array addRealNumber:[Fraction fractionWithNumerator:3 denominator:8] ];
[array addRealNumber:[Fraction fractionWithNumerator:3 denominator:2] ];
[array sort];
printf("%s\n", [[array description] UTF8String]);
}
return 0;
}