创建?个Fraction类（分数）实现分数的加减乘除，?较??、约 分等?法。要求:添加属性.

//  Fraction.h
#import <Foundation/Foundation.h>

@interface Fraction : NSObject
@property (nonatomic, assign)NSInteger above;//分子
@property (nonatomic, assign)NSInteger below;//分母
//初始化
- (id)initWithName:(NSInteger)above below:(NSInteger)below;
//最大公约数
- (NSInteger)maxGY:(NSInteger)above below:(NSInteger)below;
//约分
- (void)simply;
//相加
- (void)sumfraction:(Fraction *)fraction;
//相减
- (void)subfraction:(Fraction *)fraction;
//相乘
- (void)mulfraction:(Fraction *)fraction;
//相除
- (void)divfraction:(Fraction *)fraction;
//输出
- (NSString *)description;




@end

//  Fraction.m

#import "Fraction.h"

@implementation Fraction
//初始化
- (id)initWithName:(NSInteger)above below:(NSInteger)below{
    self = [super init];
    if (self) {
        self.above = above;
        self.below = below;
    }
    return self;
}
//最大公约数
- (NSInteger)maxGY:(NSInteger)above below:(NSInteger)below{
    NSInteger a = above % below;
    while (a != 0){
        above = below;
        below = a;
        a = above % below;
        
    }
    return below;
    
    
}
//约分
- (void)simply{
    NSInteger b = [self maxGY:self.above below:self.below];
    self.above /= b;
    self.below /= b;
    
}
//相加
- (void)sumfraction:(Fraction *)fraction{
    self.above = self.above * fraction.below + fraction.above * self.below;
    self.below = self.below * fraction.below;
    [self simply];
    
}

- (void)subfraction:(Fraction *)fraction{
    self.above = self.above * fraction.below - fraction.above * self.below;
    self.below = self.below * fraction.below;
    [self simply];
    
}
- (void)mulfraction:(Fraction *)fraction{
    self.above = self.above * fraction.above ;
    self.below = self.below * fraction.below;
    [self simply];
    
}
- (void)divfraction:(Fraction *)fraction{
    
    self.above = self.above * fraction.below ;
    self.below = self.below * fraction.above;
    [self simply];
}

//输出
- (NSString *)description{
   return [NSString stringWithFormat:@"%lu / %lu", self.above, self.below];
}










@end

//  main.m

#import <Foundation/Foundation.h>
#import "Fraction.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //创建?个Fraction类（分数）实现分数的加减乘除，?较??、约分等?法。要求：为类添加属性
    Fraction *fr1 = [[Fraction alloc]initWithName:2 below:4];
    Fraction *fr2 = [[Fraction alloc]initWithName:3 below:5];
        [fr1 sumfraction:fr2];
         NSLog(@"%@",fr1);
        [fr1 subfraction:fr2];
        NSLog(@"%@",fr1);
        [fr1 mulfraction:fr2];
        NSLog(@"%@", fr1);
        [fr1 divfraction:fr2];
        NSLog(@"%@", fr2);
        
     
        
        
        
        
        
        
      
    }
    return 0;
}