创建一个Fraction类（分数）实现分数的加减乘除，比较大小、约分等方法。

.h文件中的代码

#import <Foundation/Foundation.h>

@interface Fracton :
NSObject

{

    NSInteger molecule;//分子

    NSInteger denominator;//分母

}

@property NSInteger molecule;

@property NSInteger denominator;

-(void)reductionOfFraction;//约分

- (void)add:(Fracton *)fenshu3;//加

- (Fracton *)sub:(Fracton *)fenshu3;//减

- (void)mult:(Fracton *)fenshu3;//乘法

- (void)division:(Fracton *)fenshu3;//除法

- (void)compare:(Fracton *)fenshu3;//比较

@end

.m文件中的代码

#import "Fracton.h"

@implementation Fracton

@synthesize molecule =
_molecule;

@synthesize denominator =
_denominator;

-(void)reductionOfFraction{

    NSInteger a =
self.molecule;

    NSInteger b =
self.denominator;

    NSInteger c =
0;

    while (b != 0) {

        c = a % b;

        a = b;

        b = c;

    }

        NSLog(@"%ld/%ld",self .molecule/a,self.
denominator/a);

    }

- (void)add:(Fracton *)fenshu3{

    Fracton *fenshu2 =[Fracton
alloc];

    fenshu2.molecule = (self.molecule * fenshu3.denominator) + (fenshu3.molecule *
self.denominator);

    fenshu2.denominator =
self.denominator * fenshu3.denominator;

    [fenshu2 reductionOfFraction];

}

- (Fracton *)sub:(Fracton *)fenshu3{

    Fracton *fenshu2 =[Fracton
alloc];

    fenshu2.molecule =
self.molecule * fenshu3.denominator - fenshu3.molecule *
self.denominator;

    fenshu2.denominator =
self.denominator * fenshu3.denominator;

    [fenshu2 reductionOfFraction];

    return fenshu2;

}

- (void)mult:(Fracton *)fenshu3{

    Fracton *fenshu2 =[Fracton
alloc];

    fenshu2.molecule =
self.molecule * fenshu3.molecule;

    fenshu2.denominator =
self.denominator * fenshu3.denominator;

    [fenshu2 reductionOfFraction];

    

    

}//乘法

- (void)division:(Fracton *)fenshu3{

    Fracton *fenshu2 =[Fracton
alloc];

    fenshu2.molecule =
self.molecule * fenshu3.denominator;

    fenshu2.denominator =
self.denominator * fenshu3.molecule;

    [fenshu2 reductionOfFraction];

    

}//除法

- (void)compare:(Fracton *)fenshu3{

    Fracton *fenshu2 =[Fracton
alloc];

       fenshu2 = [self
sub:fenshu3];

    if (fenshu2.molecule >
0) {

        NSLog(@"分数1大于分数2");

    }else if(fenshu2.molecule ==
0)

    {

        NSLog(@"分数等于分数2");

    }else{

        NSLog(@"分数小于分数2");

    }

}

   @end

main函数中的实现

nt main(int argc,
const char * argv[])

{

    @autoreleasepool {

        Fracton *fenshu1 = [Fracton
alloc];

        fenshu1.molecule =
4;

        fenshu1.denominator =
6;

        Fracton *fenshu2 = [Fracton
alloc];

        fenshu2.molecule =
2;

        fenshu2.denominator =
5;

        [fenshu1 add:fenshu2];

        [fenshu1 sub:fenshu2];

        [fenshu1 mult:fenshu2];

        [fenshu1 compare:fenshu2];

        [fenshu1 reductionOfFraction];

}

  return 0;

}