class A
{
public void fcna()
{
System.out.print("a");
}
}
class B extends A {
public void fcna() { System.out.print("b"); }
}
public class main{
public static void main (String args[]) throws Exception {
A a = new A();
B b = new B();
a = b; ----------这里会有错吗?
a.fcna(); }
}
上面写的有错。
{
public void fcna()
{
System.out.print("a");
}
}
class B extends A {
public void fcna() { System.out.print("b"); }
}
public class main{
public static void main (String args[]) throws Exception {
A a = new A();
B b = new B();
a = b; ----------这里会有错吗?
a.fcna(); }
}
上面写的有错。
b = a错 a = b对