大家帮忙找下这6道C#的错，再给点解释 谢谢哈
1.******************************************************
class Program
{
public static void Main()
{
A t = new A();
int x, y;
x = 5; y = 8;
t.S(x,y);
Console.WriteLine("x={0},y={1}",x,y);
}
}
class A
{
public void S(int a, int b)
{
int temp;
temp = a; a = b; b = temp;
}
}
2.******************************************************
class A
{
static int n;
public A()
{
n++;
}
public void B()
{
Console.WriteLine(n);
}
public static void Main()
{
B();
}
3.******************************************************
class A
{
public static void Main()
{
C d = new C();
}
}
class B
{
public B()
{
Console.WriteLine("实例化B对象！");
}
}
class C : B
{
public C()
{
Console.WriteLine("实例化Dog对象！");
}
}
4.******************************************************
class Program
{
public static void Main()
{
Dog d = new Dog();
Test t = new Test();
t.Eat(d);
}
}
class Test
{
public void Eat(Animal a)
{
a.Eat();
}
}
class Animal
{
public void Eat()
{
Console.WriteLine("Eat Something!");
}
}
class Dog : Animal
{
public void Eat()
{
Console.WriteLine("Eat Bone!");
}
}
5.******************************************************
interface IUSB
{
public void Download(string file)
{ }
}
********************************************
class Mp3:IUSB
{
public void Play(string file)
{
Console.WriteLine("播放{0}",file);
}
}
6.*****************************************************
class Program
{
public static void Main()
{
Mp3 mp3 = new Mp3();
mp3.Download("test.mp3");
}
}
interface IUSB
{
void Download(string file);
}
interface IBluetooth
{
void Download(string file);
}
class Mp3:IUSB,IBluetooth
{
void IUSB.Download(string file)
{
Console.WriteLine("用USB下载{0}", file);
}
void IBluetooth.Download(string file)
{
Console.WriteLine("用Bluetooth下载{0}", file);
}
}
7.*****************************************************
class Program
{
public static void Main()
{
Math math = new Math();
Call obj;
obj = new Call(math.Add);
int r=obj(3, 5);
Console.WriteLine(r);
}
}
public delegate int Call(int a,int b);
class Math
{
public int Add(int a, int b)
{
Console.WriteLine("Add Method");
return a + b;
}
public int Sub(int a, int b)
{
Console.WriteLine("Sub Method");
return a - b;
}
}
8.*****************************************************
class Program
{
public static void Main()
{
Album friends = new Album(3); // 创建一个容量为 3 的相册
Photo first = new Photo("Jenn"); // 创建 3 张照片
Photo second = new Photo("Smith");
Photo third = new Photo("Mark");
friends[0] = first; // 向相册加载照片
friends[1] = second;
friends[2] = third;
Photo obj1Photo = friends[2]; // 按索引检索
Console.WriteLine(obj1Photo.Title);
Photo obj2Photo = friends["Jenn"]; // 按名称检索
Console.WriteLine(obj2Photo.Title);
}
}
class Photo
{
string _title;
public Photo(string title)
{
this._title = title;
}
public string Title
{
get
{
return _title;
}
}
}
class Album
{
Photo[] photos;
public Album(int capacity)
{
photos = new Photo[capacity];
}
}
9.*****************************************************
class Program
{
public static void Main()
{
ArrayList al = new ArrayList();
A a=new A(3);al.Add(a);
A b=new A(4);al.Add(b);
A c=new A(5);al.Add(c);
al.RemoveAt(0);
al.RemoveAt(1);
foreach (object obj in al)
{
A aa = (A)obj;
Console.WriteLine(aa.no);
}
}
}
class A
{
public int no;
public A(int no)
{
this.no = no;
}
}
[解决办法]
第一题想输出x=8,y=5?class Program { public static void Main() { A t = new A(); int x, y; x = 5; y = 8; t.S(x, y); Console.WriteLine("x={0},y={1}", x, y); Console.Read(); } } class A { public void S(int a, int b) { int temp; temp = a; a = b; b = temp; } } 建议看下值传递与引用传递第二题无法引用方法B的错误？编译的时候已经提示了无法引用非静态的字段或属性，将方法B声明成静态的public static void B()第三题什么错误？建议让别人改错的时候写上啥错误，和期待的正确结果第四题想输出Eat Bone!？这样写public virtual void Eat()public override void Eat()第五题干什么的？第六题：class Program { public static void Main() { IUSB mp3 = new IUSBMp3(); mp3.Download("test.mp3"); IUSB mp32 = new IBluetoothMp3(); mp3.Download("tt"); Console.Read(); } } interface IUSB { void Download(string file); } interface IBluetooth { void Download(string file); } class IUSBMp3 : IUSB { public void Download(string file) { Console.WriteLine("用USB下载{0}", file); } } class IBluetoothMp3 : IUSB { public void Download(string file) { Console.WriteLine("用Bluetooth下载{0}", file); } }第七题委托题？没接触过直接忽略嘿嘿第八题：class Program { public static void Main() { Album album = new Album(3); // 创建一个容量为 3 的相册 Photo[] friends = album.photos; Photo first = new Photo("Jenn"); // 创建 3 张照片 Photo second = new Photo("Smith"); Photo third = new Photo("Mark"); friends[0] = first; // 向相册加载照片 friends[1] = second; friends[2] = third; Photo obj1Photo = friends[2]; // 按索引检索 Console.WriteLine(obj1Photo.Title); //下边的错误是因为数组不支持用名称检索 Photo obj2Photo = friends["Jenn"]; // 按名称检索 Console.WriteLine(obj2Photo.Title); Console.Read(); } } class Photo { string _title; public Photo(string title) { this._title = title; } public string Title { get { return _title; } } } class Album { public Photo[] photos; public Album(int capacity) { photos = new Photo[capacity]; } } 第九题： A a = new A(3); al.Add(a); A b = new A(4); al.Add(b); A c = new A(5); al.Add(c); al.RemoveAt(0); al.RemoveAt(1); al.RemoveAt(0);//删除a al.RemoveAt(1);//删除c所以输出4你认为输出5是不是?编译正确不知道你所指的错误是什么
[解决办法]
看了下，补充楼上的第4题，如果是写出输出什么，那么应该是Eat Something!!,因为函数没有被重写，还是调用基类的函数第5题：接口的方法是不需要修饰符的，而且也不需要实现，所以正确写法是：interface IUSB { void Download(string file)； } 第6题：这题考的是，如果接口含有相同方法，那么该如何去继承和调用继承的时候，是不能加修饰符public的，只能是private,题目上写法是正确的，关键就是调用的时候他写错了，正确写法:class Program { public static void Main() { Mp3 mp3 = new Mp3(); ((IUSB)mp3).Download("test.mp3");//调用IUSB接口的方法 ((IBluetooth)mp3).Download("test.mp3");//调用IBluetooth接口方法 } } 第七题：这程序没问题，可能考的是输出什么，结果是：8 委托的用法其余的Up