问题描述

Objective C中没有声明的标示符

实在是不知道该怎么绕过这个错误，总是说：use of undeclared identifier 'ageBy'。请高手帮我指点一下吧，先看看我的代码：

Person.h

@interface Person : NSObject{ int _age; int _years; NSString *_name; NSString *_job;} -(void)setAge:(int)age;-(int)age;-(void)setName:(NSString *)name;-(NSString *)name;-(void)setJob:(NSString *)job;-(NSString *)job;-(NSString *)summaryString;-(void)ageBy:(int)years;@end

Person.m

#import ""Person.h""@implementation Person-(void)setAge:(int)age{  _age = age;}-(int)age{  return _age;}-(void)setName:(NSString *)name{  _name = name;}-(NSString *)name{  return _name; }-(void)setJob:(NSString *)job{  _job = job;}-(NSString *)job{  return _job;}-(NSString *)summaryString{  return [NSString stringWithFormat:@""The Person %@ is %d years old and is a  %@""_name_age_job];-(void)ageBy:(int)years{  _years = years;  _age = years + _age; } }  @end

解决方案

你的ageBy是在summaryString中定义的，应该移动{}括号到@end之前，这样它就在
-(void)ageBy:(int)years中了，

-(NSString *)summaryString{  return [NSString stringWithFormat:@""The Person %@ is %d years old and is a  %@""_name_age_job]; } -(void)ageBy:(int)years{  _years = years;  _age = years + _age; }