Objective-C 类基础(二)

这次构建一个Fraction类，实现如下

#import <Foundation/Foundation.h>
@interface Fraction:NSObject
{
@private//访问权限有public，protected,private ,三种，若未指定，缺省为protected
int numbertor;
int denomiator;
}

-(void) print;
-(void) setNumerator: (int) n;
-(void) setDenomiator: (int) d;
//数据封装
-(int)numbertor;
-(int)denomiator;

-(double) converToNum;
@implementation Fraction
-(void) print{
//return ((@"%i/%i",numbertor,denomiator));
NSLog(@"%i/%i",numbertor,denomiator);
}

-(void) setNumerator: (int) n{
numbertor=n;
return ;
}

-(void) setDenomiator:(int)d{
denomiator=d;
return ;
}

-(int)numbertor{
return numbertor;
}

-(int)denomiator{
return denomiator;
}

-(double) converToNum{
if(denomiator!=0){
return (double) numbertor/denomiator;
}
else return NAN;//NAN 表示未定义的数
}
@end
int main(int argc, const char * argv[])
{

@autoreleasepool {
Fraction *myFraction=[[Fraction alloc] init];
[myFraction setNumerator:1];
[myFraction setDenomiator:3];

NSLog(@"The value is");
[myFraction print];
NSLog(@"%i/%i ",[myFraction numbertor],[myFraction denomiator]);

}
return 0;
}