C++类继承中的虚方法

 #include <bits/stdc++.h>
 using namespace std;

 class A {
     public:
         void Show() {
             cout << "A" << endl;
         }
 } ;

 class B : public A {
     public:
         virtual void Show() {
             cout << "B" << endl;
         }
 } ;

 class C : public B {
     public:
         void Show() {
             cout << "C" << endl;
         }
 } ;

 int main() {
     A a; B b; C c;
     A &s1 = b; A &s2 = c;
     B &t1 = b; B &t2 = c;
     s1.Show(); s2.Show();
     t1.Show(); t2.Show();
     return ;
 }

 #include <bits/stdc++.h>
 using namespace std;

 class A {
     public:
         virtual void Show() { // 将virtual去掉运行做对比
             cout << "A" << endl;
         }
 } ;

 class B : public A {
     public:
         virtual void Show() {
             cout << "B" << endl;
         }
 } ;

 class C : public A {
     public:
         void Show() {
             cout << "C" << endl;
         }
 } ;

 class D : public A {
 } ;

 int main() {
     ios::sync_with_stdio();
     A a; B b; C c; D d;
     A &t1 = a; A &t2 = b; A &t3 = c; A &t4 = d;
     t1.Show(); t2.Show(); t3.Show(); t4.Show();
     a.Show(); b.Show(); c.Show(); d.Show();
     return ;
 }

——written by Lyon