＋号级别得成员方法实现
Demo：加号级别的成员方法的实现：
#import <Foundation/Foundation.h>
@interface Person:NSObject
{
????? int _age;
}
-(id)initWithAge:(int)age;
+(id)personWithAge:(int)age;
-(void)print;
@end
?
@implementation Person
?
-(id)initWithAge:(int)age
{
????? self = [super init];
????? if (nil != self) {
???????? _age = age;
????? }
????? return self;
}
+(id)personWithAge:(int)age
{??? //返回id类型和用到self是为子类考虑,子类继承Person,当调用该方法是返回的是子类的对象
????? //在+级别的方法中,一般用self
????? id obj = [[self alloc] initWithAge:age];
????? return [obj autorelease];
?????
}
-(void)print
{
????? NSLog(@"age = %d",_age );
}
@end
?
@interface Student : Person
@end
?
@implementation Student
@end
?
?
int main (int argc, const char * argv[]) {
??? NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
?????
????? Person* p = [Person personWithAge:20];
????? [p print];
?????
????? Student* stu = [Student personWithAge:30];
????? NSLog(@"%@", NSStringFromClass([stu class]));
????? [stu print];
??
??? [pool drain];
??? return 0;
}
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