9

package test;

class AddClass
{
public int x=0,y=0,z=0;
AddClass (int x)
{ this.x=x; }
AddClass (int x,int y)
{ this(x); this.y=y; } //调用第一个构造方法
AddClass (int x,int y,int z)
{ this(x,y); this.z=z; } //调用第二个构造方法
public int add()
{return x+y+z; }
}

public class SonAddClass extends AddClass
{ int a=0,b=0,c=0;
SonAddClass (int x)
{ super(x); a=x+7; }
SonAddClass (int x,int y)
{ super(x,y); a=x+5; b=y+5; }
SonAddClass (int x,int y,int z)
{ super(x,y,z); a=x+4; b=y+4; c=z+4;}
public int add()
{System.out.println("super:x+y+z="+super.add());
return a+b+c;
}
public static void main(String[] args)
{ SonAddClass p1=new SonAddClass (2,3,5);
SonAddClass p2=new SonAddClass (10,20);
SonAddClass p3=new SonAddClass (1);
System.out.println("a+b+c="+p1.add());
System.out.println("a+b="+p2.add());
System.out.println("a="+p3.add());
}
}