C#的两个简单问题
刚学习C#，希望高手多多指教！
第一个问题：
class test
{
static void Main(string[] args)
{
B b = new B();
}
}
class A
{
public A()
{
PrintFields();
}
public virtual void PrintFields() { }
}
class B : A
{
int x = 1;
int y;
public B()
{
y = -1;
}
public override void PrintFields()
{
Console.WriteLine("x={0},y={1}", x, y);
}
}
为什么输出的结果是：x=1,y=0
当实例化B的时候程序是怎样执行的？
第二个问题：
class chongzai
{
private double x;
private double y;
private double z;
public chongzai()
{
x = 0;
y = 0;
z = 0;
}
public chongzai(double x, double y, double z)
{
this.x = x;
this.y = y;
this.z = z;
}
public chongzai(chongzai ch)
{
x = ch.x;
y = ch.y;
z = ch.z;
}
public static chongzai operator +(chongzai ch1, chongzai ch2)
{
ch1.x += ch2.x;
ch1.y += ch2.y;
ch1.z += ch2.z;
return ch1;
}
public override string ToString()
{
return "x的坐标是" + x + "y的坐标是" + y + "z的坐标是" + z;
}
public static bool operator ==(chongzai ch1, chongzai ch2)
{
if (ch1.x == ch2.x && ch1.y == ch2.y && ch1.z == ch2.z)
{
return true;
}
else
{
return false;
}
}
public static bool operator !=(chongzai ch1, chongzai ch2)
{
return !(ch1 == ch2);
}
static void Main(string[] args)
{
chongzai ch0 = new chongzai(1, 2, 3);
chongzai ch1 = new chongzai(1, 2, 3);
Console.WriteLine(ch1.ToString());
chongzai ch2 = new chongzai(ch1);
Console.WriteLine(ch2.ToString());
chongzai ch3;
ch3 = ch1 + ch2;
bool bl = (ch0 == ch1);
Console.WriteLine(bl);
if (ch1 == ch2)
{
Console.WriteLine("you are right,they are equal");
}
else
{
Console.WriteLine("they are not equal");
}
Console.WriteLine(ch3.ToString());
}
}
那个比较运算符重载有问题，为什么b1会输出false bool bl = (ch0 == ch1); 问题在哪？
恳请热心人帮忙解答，谢谢啦！
[解决办法]
为什么输出的结果是：x=1,y=0
当实例化B的时候程序是怎样执行的？
----
先执行基类的构造函数,再扩行派生类的构造函数,基类构造函数就进行输出的时候,你的y还没有初始化,所以为0
[解决办法]
为什么b1会输出false bool bl = (ch0 == ch1); 问题在哪？
---------------------
问题在这里
ch3 = ch1 + ch2;
ch1为引用类型,在这里你重载的加法.实际已经改变了你ch1对象的值.所以ch1已经不为其初始值了
在这里你的ch1==ch3的.你不信可以输出试试看
[解决办法]
try
public static chongzai operator +(chongzai ch1, chongzai ch2) { chongzai result=new chongzai(); result.x=ch1.x+ch2.x; result.y=ch1.y+ch2.y; result.z=ch1.z+ch2.z; return result; }