class Box
{
int i;
int j;
Box()
{
i = 10;
j = 10;
}
public void show()
{
System.out.println( i+"\t"+j );
}
}
class wBox extends Box
{
int weight = 50;
wBox()
{
super();
}
protected void show()
{
System.out.println( i+"\t"+j+"\t"+weight );
}
}
public class t1
{
public static void main(String args[])
{
wBox mybox = new wBox();
mybox.show();
} }
{
int i;
int j;
Box()
{
i = 10;
j = 10;
}
public void show()
{
System.out.println( i+"\t"+j );
}
}
class wBox extends Box
{
int weight = 50;
wBox()
{
super();
}
protected void show()
{
System.out.println( i+"\t"+j+"\t"+weight );
}
}
public class t1
{
public static void main(String args[])
{
wBox mybox = new wBox();
mybox.show();
} }
解决思路:
1.将show修饰符改为public 这样相当于overload父类的方法
2.将show方法的参数改为非空值,这样相当于override父类的show方法