get,set初始化的描写

-(id) variable{

return （varibale）

}

-(void)setVariable:(object)newVariable{

 

　　[newVariable retain];

　　[variable release];

     variable=newVariable;

}

-(Trie *) tireAtIndex:(int) index{

Tire *tire;

tire=[tires objectAtIndex:index];

return (tire);

}

 

 

-(void)setTire:(Tire *)tire

         (int) atIndex{

[Tires replaceObjectAtIndex:index

         withObject tire];

 

}