OC语言--继承、点语法、类别

                @interface Person : NSObject//NSObject 根类
		{
			@protected//受保护的:，
							// 子类继承父类之后，
							// 子类可以直接使用父类的受保护成员变量
    			int _age;
			@public//公有的:类内和类外的函数 
						//都可以直接使用公有的成员变量
						//这将一定程度上破坏对象信息的隐藏性
    			int _height;
			@private//私有的:  类内减方法可以直接使用私有的
						// 类外的方法不能直接使用，
						// 但是可以通过实例方法间接访问和使用，
						// 子类继承父类之后，
						// 子类可以通过父类的方法间接使用父类私有的变量
   				int _money;
		}

//类别的声明部分

@interface  NSString(Print)

-(void)print;//增加的新方法（不能有成员变量的声明）

...

@end

 

//类别实现部分

@implementation NSString(Print)

-(void)print{

 

}

…

@end

@interface Person()//没有名字

  - (void)song;

@end

 
@implementation Person

- (void)song{

NSLog(@"hello");

}

@end

#import <Foundation/Foundation.h>
#define RATE 0.0325
@interface Account : NSObject{
  NSUInteger _uid;//用户账号
  NSString* _upasswd;//用户密码
  double _uamount;//账户余额
  double _uperiod;//储蓄时间
  double _rate;//一年期的存款利率
}
@property (assign,nonatomic) NSUInteger uid;
@property (copy,nonatomic) NSString* upasswd;
@property (assign,nonatomic) double uamount;
@property (assign,nonatomic) double uperiod;
@property (assign,nonatomic) double rate;
- (void)deposit:(double)money;//存款
- (double)withdraw:(double)money;//提款
- (double)settlementOnWithdraw:(double)money;//取款时结算利息
- (double)settlementUponYear;//年度结算利息
- (double)interestCaculate;//利息计算
- (double)incomeCaculate;//到期本息收益
+ (void)testBySelf;//本类的自测方法
- (id)initWithUid:(NSUInteger)aUid andUpasswd:(NSString*)aUpasswd andUamount:(double)aUamount;

@end

#import "Account.h"

@interface Account (currency)
- (void)deposit:(double)money withForeignCurrency:(char)type;//存款
- (double)withdraw:(double)money withForeignCurrency:(char)type;//提款
@end

#import "Account.h"
#import "Account+currency.h"
  //#include "Account_dollar.h"

@implementation Account
@synthesize uid=_uid;
@synthesize uamount=_uamount;
@synthesize upasswd=_upasswd;
@synthesize rate=_rate;
@synthesize uperiod=_uperiod;

- (void)deposit:(double)money{
  _uamount += money;
  NSLog(@"存款后的当前账户余额：%.2lf",_uamount);
}

- (double)withdraw:(double)money{
  _uamount += [self settlementOnWithdraw:_uamount];
  _uamount -= money;
  NSLog(@"取款后的当前账户余额：%.2lf",_uamount);
  return _uamount;
}
- (double)settlementOnWithdraw:(double)money//取款时结算利息
{
  double RetMoney = money;
  
  return RetMoney *= (_rate * _uperiod);
}
- (double)settlementUponYear//年度结算利息
{
  
  return _uamount *= (1+_rate);
}
- (double)interestCaculate//到期利息计算
{
  double interest = 0.0;
  
  return interest = _uamount * _rate;
}
- (double)incomeCaculate//到期本息收益
{
  double income = 0.0;

  return income = _uamount*(1+_rate);
}
+ (void)testBySelf//本类的自测方法
{
    //新建一个账户实例
  Account* aAccount = [[Account alloc]init];
    //显示账户初始状态
  NSLog(@"%@",aAccount);
    //存款测试
  [aAccount deposit:100.00];
  NSLog(@"%@",aAccount);
    //模拟的日期间隔
  int n = 36;
  for(int i=1;i<=n;i++){
    aAccount.uperiod = (double)i/(double)365;
  }

    //取款测试
  [aAccount withdraw:50.00];
  NSLog(@"%@",aAccount);
    //模拟存一笔前，并到一年期
  [aAccount deposit:100.00];
    //模拟时间流逝
  for(int i=n;i<=365;i++){
    aAccount.uperiod = (double)i/(double)356;
  }
  [aAccount settlementUponYear];
   NSLog(@"%@",aAccount);
    //外币存款
//  aAccount.foreign_amount = 1.0;
  [aAccount deposit:200.00 withForeignCurrency:‘$‘];
  
}
- (id)initWithUid:(NSUInteger)aUid andUpasswd:(NSString*)aUpasswd andUamount:(double)aUamount{
  if (self = [super init]) {
    _rate = RATE;
    _uperiod = 1/365;
    _uid = aUid;
    _upasswd = aUpasswd;
    _uamount = aUamount;
  }
  
  return self;
}
-(id)init
{
  return [self initWithUid:1 andUpasswd:@"123456" andUamount:1.0];
}
- (NSString *)description
{
  NSString* passwd_des = @"******";
  
  return [NSString stringWithFormat:@"用户账号：%06lu 用户口令：%@ 账户余额：%.2lf（元） 当前定期存款利率（一年期）：%.4lf 存储时间：%.2lf(年)", _uid,passwd_des,_uamount,_rate,_uperiod];
}
@end

#import "Account+currency.h"
#import "Account_dollar.h"

@implementation Account (currency)
  //外币存款方法
- (void)deposit:(double)money withForeignCurrency:(char)type//存款
{
  double fa = self.foreign_amount;
  fa += money;
  self.foreign_amount = fa;
  NSLog(@"存款后的当前外币(%c)账户余额：%.2lf",type,self.foreign_amount);
}
  //外币取款方法有 bug，请自行修改正确！！！
- (double)withdraw:(double)money withForeignCurrency:(char)type//提款
{
  self.foreign_amount += [self settlementOnWithdraw:self.foreign_amount];
  self.foreign_amount -= money;
  NSLog(@"取款后的当前外币(%c)账户余额：%.2lf",type,self.foreign_amount);
  return self.foreign_amount;
}


@end

#import "Account.h"

@interface Account (){
  char _currency_type;
  double _foreign_rate;
  double foreign_amount;
}
@property (assign) char currency_type;
@property (assign) double foreign_rate;
@property (assign) double foreign_amount;

@end