在O-C中子类可以继承父类的方法 ，而不需要从新编写相同的方法，但是有有时候子类并不想原封不动的继承父类的方法，而且是想做一些修改，这就采用啦方法的重写，方法从写有叫做方法覆盖，若子类的中的方法与父类中的某一个方法具有相同的方法名，返回值类型和参数表，则新方法就会把原有的方法覆盖。
父类：
#import "MyViewController.h"
@interface MyViewController ()
@end
@implementation MyViewController
- (void)viewDidLoad
{
[superviewDidLoad];
[selfsetX];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[superdidReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)setX
{
int a = 10;
NSLog(@"A类方法的值:%zi",a);
}
@end
子类：
#import "MyBclassViewController.h"
@interface MyBclassViewController ()
@end
@implementation MyBclassViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [superinitWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[superviewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[superdidReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)setX
{
int a = 100;
NSLog(@"B类A的值：%zi",a);
}