设计类-班级

1. 设计要求见.h文件。

Student.h

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Heiti SC Light'; color: #008400}p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #008400}p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #703daa}p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}span.s1 {font-variant-ligatures: no-common-ligatures; color: #78492a}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s4 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s5 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures}span.s6 {font-variant-ligatures: no-common-ligatures; color: #000000}span.s7 {font-variant-ligatures: no-common-ligatures; color: #4f8187}

#import 

@interface Student : NSObject

{
   NSString *_name;
   NSInteger _num;
   NSInteger _score;
   
}

//构造方法
-(id)initWithName:(NSString *)name number:(NSInteger)num score:(NSInteger)score;

//setter
-(void)setName:(NSString *)name;
-(void)setNum:(NSInteger)num;
-(void)setScore:(NSInteger)score;

//getter
-(NSString *)name;
-(NSInteger)num;
-(NSInteger)score;

//功能方法
-(BOOL)isSortByScore:(Student *)aStudent;
-(bool)isSortByNum:(Student *)aStudent;
-(NSComparisonResult)isSortByName:(Student *)aStudent;

-(void)printStudnent;

@end

MyClass.h

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}span.s1 {font-variant-ligatures: no-common-ligatures; color: #78492a}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s4 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s5 {font-variant-ligatures: no-common-ligatures; color: #4f8187}

#import 
#import "Student.h"

@interface MyClass : NSObject
{
   NSString *_className;
   NSMutableArray *_stuList;
}

-(id)initWithClassName:(NSString *)name;

-(void)setClassName:(NSString *)name;
-(NSString *)className;

-(void)addStudent:(Student *)astudent;
-(void)addStudent:(Student *)astudent atIndex:(NSInteger)index;
-(void)removeStudent:(Student *)astudent;
-(void)removeStudentAtIndex:(NSInteger)index;
-(void)replaceStudent:(Student *)astudent atIndex:(NSInteger)index;

-(void)showStuList;

-(void)sortedByNumber;
-(void)sortedByScore;
-(void)sortedByName;

+(void)testMyClass;

@end

2. .m实现文件(有问题)

Student.m

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Heiti SC Light'; color: #008400}p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #008400}p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #703daa}span.s1 {font-variant-ligatures: no-common-ligatures; color: #78492a}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font-variant-ligatures: no-common-ligatures; color: #000000}span.s4 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures}span.s5 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s6 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s7 {font-variant-ligatures: no-common-ligatures; color: #4f8187}span.s8 {font-variant-ligatures: no-common-ligatures; color: #31595d}span.s9 {font-variant-ligatures: no-common-ligatures; color: #008400}span.s10 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures; color: #008400}span.s11 {font-variant-ligatures: no-common-ligatures; color: #3d1d81}

#import "Student.h"

@implementation Student
//构造方法
-(id)initWithName:(NSString *)name number:(NSInteger)num score:(NSInteger)score
{
   self = [super self];
   if (self) {
       _name=name;
       _num=num;
       _score=score;
   }
   return self;
}

//setter
-(void)setName:(NSString *)name
{
   _name=name;
}
-(void)setNum:(NSInteger)num
{
   _num=num;
}
-(void)setScore:(NSInteger)score
{
   _score=score;
}

//getter
-(NSString *)name
{
   return _name;
}
-(NSInteger)num
{
   return  _num;
}
-(NSInteger)score
{
   return _score;
}

//功能方法
-(BOOL)isSortByScore:(Student *)aStudent
{
   if ([self score]>[aStudent score]) {    //调用者分数>参数分数
       return YES;
   }
   else
       return NO;
}
-(bool)isSortByNum:(Student *)aStudent
{
   if ([self num]>[aStudent num]) {
       return YES;
   }
   else
       return NO;
}
-(NSComparisonResult)isSortByName:(Student *)aStudent
{
   return [[self name] compare:[aStudent name]];
}

-(void)printStudnent
{

   NSLog(@"name=%@, num=%li, score=%li",[self name],[self num],[self score]);
}
@end

MyClass.m

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #4f8187}p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #3d1d81}p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Heiti SC Light'; color: #008400}span.s1 {font-variant-ligatures: no-common-ligatures; color: #78492a}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font-variant-ligatures: no-common-ligatures; color: #000000}span.s4 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s5 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s6 {font-variant-ligatures: no-common-ligatures; color: #4f8187}span.s7 {font-variant-ligatures: no-common-ligatures; color: #3d1d81}span.s8 {font-variant-ligatures: no-common-ligatures; color: #008400}span.s9 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures; color: #008400}span.s10 {font-variant-ligatures: no-common-ligatures; color: #d12f1b}span.s11 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures}span.s12 {font-variant-ligatures: no-common-ligatures; color: #31595d}span.s13 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures}span.s14 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures; color: #d12f1b}span.s15 {font-variant-ligatures: no-common-ligatures; color: #272ad8}

#import "MyClass.h"

@implementation MyClass

-(id)initWithClassName:(NSString *)name
{
   self=[super self];
   if (self) {
       _className=name;
   }
   return self;
}

-(void)setClassName:(NSString *)name
{
   _className=name;
}
-(NSString *)className
{
   return _className;
}

-(void)addStudent:(Student *)astudent
{
   if (![_stuList containsObject:astudent]) {
       [_stuList addObject:astudent];
   }
}
-(void)addStudent:(Student *)astudent atIndex:(NSInteger)index
{
   if (![_stuList containsObject:astudent]) {
       [_stuList insertObject:astudent atIndex:index];
   }
}
-(void)removeStudent:(Student *)astudent
{
   if ([_stuList containsObject:astudent]) {
       [_stuList removeObject:astudent];
   }
}
-(void)removeStudentAtIndex:(NSInteger)index
{

   [_stuList removeObjectAtIndex:index];
}
-(void)replaceStudent:(Student *)astudent atIndex:(NSInteger)index
{
   [_stuList replaceObjectAtIndex:index withObject:astudent];
}

-(void)showStuList  //遍历可变数组
{
   NSLog(@"111");
   NSLog(@"学生列表：%@",_stuList);
   Student *obj;
   for(obj in _stuList)
   {
       [obj printStudnent];
   }
   
}

-(void)sortedByNumber //降序排列
{
   [_stuList sortUsingSelector:@selector(isSortByNum:)];
}
-(void)sortedByScore
{
   [_stuList sortUsingSelector:@selector(isSortByScore:)];
}
-(void)sortedByName
{
   [_stuList sortUsingSelector:@selector(isSortByName:)];
}

//类方法
+(void)testMyClass
{
   MyClass *iosClass=[[MyClass alloc]initWithClassName:@"ios班级"];
   for (NSInteger i=0; i<10; i++) {
       Student *stu = [[Student alloc]initWithName:[NSString stringWithFormat:@"stu%d",arc4random()%50+1] number:arc4random()%100+1 score:arc4random()%101];
       [iosClass addStudent:stu];
   }
   NSLog(@"---排序前----");
   [iosClass showStuList];
}

@end

main函数

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}span.s1 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font-variant-ligatures: no-common-ligatures; color: #000000}span.s4 {font-variant-ligatures: no-common-ligatures; color: #4f8187}span.s5 {font-variant-ligatures: no-common-ligatures; color: #31595d}span.s6 {font-variant-ligatures: no-common-ligatures; color: #272ad8}

int main(int argc, const char * argv[]) {
   @autoreleasepool {
       [MyClass testMyClass];
   }
   return 0;
}

一开始直接调用[MyClass testMyClass]，没有打印出排序前的课程信息。在几个关键语句前加了测试输出函数，发现问题出在MyClass类中的addStudent方法。可以成功调用并运行这个函数，但是运行结束后学生列表仍为空。
测试输出结果如下图：

屏幕快照 2016-10-13 下午6.47.02.png

3. 代码修改

针对之前的问题，浏览了一遍代码，首先发现了两个低级错误，就是在构造函数中把 self = [super init] 错写成了 self = [super self]，修改之后输出结果没变化。

因为输出结果是学生列表指针为空，所以我首先想到的是Class类中添加学生到列表的函数出错

(void)addStudent:(Student *)astudent

仔细检查并重写了个简单的test函数，发现这个函数没错，我就开始检查学生列表 _stuList的初始化问题。发现在Class构造函数中没有初始化这个列表，所以指针一直为空。
所以将MyClass.m中的构造函数修改为：

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}span.s1 {font-variant-ligatures: no-common-ligatures}span.s2 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s3 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s4 {font-variant-ligatures: no-common-ligatures; color: #3d1d81}span.s5 {font-variant-ligatures: no-common-ligatures; color: #4f8187}span.s6 {font-variant-ligatures: no-common-ligatures; color: #008400}span.s7 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures; color: #008400}span.s8 {font-variant-ligatures: no-common-ligatures; color: #000000}

-(id)initWithClassName:(NSString *)name
{
   self=[super init];
   if (self) {
       _className=name;
       //创建可变数组
       _stuList= [NSMutableArray array];
   }
   return self;
}

再次运行，结果正确。

屏幕快照 2016-10-14 下午8.00.04.png

之后在test函数加入测试排序功能：

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}span.s1 {font-variant-ligatures: no-common-ligatures; color: #000000}span.s2 {font-variant-ligatures: no-common-ligatures; color: #3d1d81}span.s3 {font-variant-ligatures: no-common-ligatures}span.s4 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures}span.s5 {font-variant-ligatures: no-common-ligatures; color: #31595d}

   NSLog(@"---排序前----");
   [iosClass showStuList];
   
   NSLog(@"---name降序排序----");
   [iosClass sortedByName];
   [iosClass showStuList];
   
   NSLog(@"---number升序排序----");
   [iosClass sortedByNumber];
   [iosClass showStuList];
   
   NSLog(@"---score升序排序----");
   [iosClass sortedByScore];
   [iosClass showStuList];
   

得到正确结果：

屏幕快照 2016-10-14 下午8.02.27.png