一。 向上转型:
class a
{
}
class b extends a
{
}
aa = new a();
bb = new b();
aa = (a) bb;
二。 向下转型:
class a
{
}
class b extends a
{
}
a aa = new a();
b bb = new b();
b cc;
aa = ( a) bb;
cc = (b) aa;
一。 向上转型:
class a
{
}
class b extends a
{
}
aa = new a();
bb = new b();
aa = (a) bb;
二。 向下转型:
class a
{
}
class b extends a
{
}
a aa = new a();
b bb = new b();
b cc;
aa = ( a) bb;
cc = (b) aa;