@property@synthesize的含义以及误区。

@property (nonatomic,assign)NSInteger age;@property (nonatomic,retain)NSString * name;@property (nonatomic,copy)NSString * bb;

.m文件中

//如果不加以下三行，就报会找不到_age,_name,_bb变量的错误@synthesize age = _age;@synthesize name = _name;@synthesize bb =_bb;- (void)setName:(NSString *)name{    if (_name!=name) {        [_name release];        _name = [name retain];    }}- (NSString *)name{    return [[_name retain] autorelease];}- (void)setAge:(NSInteger)age{    _age = age;}- (NSInteger)age{    return _age;}- (void)setBb:(NSString *)bb{    if (_bb!=bb) {        [_bb release];        _bb = [bb copy];    }}- (NSString *)bb{    return [[_bb retain]autorelease];}

总结：一定要分清属性和变量的区别，不能混淆。@synthesize 声明的属性=变量。意思是，将属性的setter,getter方法，作用于这个变量。