OC组合问题 - 黑马程序员技术交流社区

//人
@interface Person : NSObject
{
NSString *_name; // 姓名
int _age; // 年龄
}
// 姓名的getter和setter
- (void)setName:(NSString *)name;
- (NSString *)name;
// 年龄的getter和setter
- (void)setAge:(int)age;
- (int)age;
// 同时设置姓名和年龄
- (void)setName:(NSString *)name andAge:(int)age;
@end
@implementation Person
// 姓名的getter和setter
- (void)setName:(NSString *)name
{
_name = name;
}
- (NSString *)name
{
return _name;
}
// 年龄的getter和setter
- (void)setAge:(int)age
{
_age = age;
}
- (int)age
{
return _age;
}
// 同时设置姓名和年龄
- (void)setName:(NSString *)name andAge:(int)age
{
_name = name;
_age = age;
/*
[self setName:name];
[self setAge:age];
*/
}
@end
// 书
@interface Book : NSObject
{
NSString *_name; // 书名
NSString *_publisher; // 出版社名称
Person *_author; // 作者
}
// 书名的getter和setter
- (void)setName:(NSString *)name;
- (NSString *)name;
// 出版社名称的getter和setter
- (void)setPublisher:(NSString *)publisher;
- (NSString *)publisher;
// 作者的getter和setter
- (void)setAuthor:(Person *)author;
- (Person *)author;
@end
@implementation Book
// 书名的getter和setter
- (void)setName:(NSString *)name
{
_name = name;
}
- (NSString *)name
{
return _name;
}
// 出版社名称的getter和setter
- (void)setPublisher:(NSString *)publisher
{
_publisher = publisher;
}
- (NSString *)publisher
{
return _publisher;
}
// 作者的getter和setter
- (void)setAuthor:(Person *)author
{
_author = author;
}
- (Person *)author
{
return _author;
}
@end
int main(int argc, const char * argv[])
{
Person *p = [Person new];
[p setName:@"人名" setAge:20];
NSLog(@"name=%@ --- age=%d\n",[p name], [p age]);
Book *b = [Book new];
[b setBookname:@"bookname"];
[b setAuthor: p];
NSLog(@"bookname=%@ -- author=%@",[b bookname],[b author]);//问题代码
return 0;
}

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int main(int argc, const char * argv[])
{
Person *p = [Person new];
[p setName:@"人名" andAge:20]; //同时设置人名和年龄
NSLog(@"name=%@ --- age=%d\n",[p name], [p age]);
Book *b = [Book new];
[b setName:@"bookname"]; //设置书名
[b setAuthor: p];
NSLog(@"bookname=%@ -- author=%@",[b name],[b author]);//细心点儿，你在main里写的方法名跟类的声明和实现中的方法名都不一样。
return 0;
}

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//author的对象方法：
- (NSString *)description
{
return [NSString stringWithFormat:@"name = %@ , age = %d" , _name , _age];
}

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