self关键字

作用1

• 例：

  
  
  #import <Foundation/Foundation.h>
  
  @interface People : NSObject
  
  {
  
      int _age;
  
  }
  
  - (void)setAge:(int)age;
  
  - (int)age;
  
  @end
  
  @implementation People
  
  - (void)setAge:(int)age
  
  {
  
      _age = age;
  
  }
  
  - (int)age
  
  {
  
      int _age = 10;
  
      return self->_age;
  
  }
  
  @end
  
  int main()
  
  {
  
      People *p = [People new];
  
      [p setAge:26];
  
      int age = [p age];
  
      NSLog(@"年龄为：%d",age);
  
      return 0;
  
  }

作用2

• 例

  
  
  #import <Foundation/Foundation.h>
  
  @interface People : NSObject
  
  - (void)fun1;
  
  - (void)fun2;
  
  @end
  
  @implementation People
  
  - (void)fun1
  
  {
  
      NSLog(@"执行了第一个方法");
  
      [self fun2];
  
  }
  
  - (void)fun2
  
  {
  
      NSLog(@"执行了第二个方法");
  
  }
  
  @end
  
  int main()
  
  {
  
      People *p = [People new];
  
      [p fun1];
  
      return 0;
  
  }

作用3

• 例

  
  
  #import <Foundation/Foundation.h>
  
  @interface People : NSObject
  
  + (void)fun1;
  
  + (void)fun2;
  
  @end
  
  @implementation People
  
  + (void)fun1
  
  {
  
      NSLog(@"执行了第一个类方法");
  
      [self fun2];
  
  }
  
  + (void)fun2
  
  {
  
      NSLog(@"执行了第二个类方法");
  
  }
  
  @end
  
  int main()
  
  {
  
      [People fun1];
  
      return 0;
  
  }