fix comment error and polish cout str

Author: Aurelius84

practical_exercises/10_day_practice/day6/虚函数/虚函数特性.cpp

@@ -3,28 +3,28 @@
 using namespace std;
 class A { 
 public: 
-    void f(int i){cout<<"…A"<<endl;}; 
+    void f(int i){cout<<"A::f()"<<endl;};
 };
 class B: public A { 
 public:
-    virtual void f(int i){cout<<"…B"<<endl;}
+    virtual void f(int i){cout<<"B::f()"<<endl;}
 };
 class C: public B {
 public: 
-    void f(int i){cout<<"…C"<<endl;}
+    void f(int i){cout<<"C::f()"<<endl;}
 };
 //一旦将某个成员函数声明为虚函数后，它在继承体系中就永远为虚函数了 
 class D: public C{
 public:
-    void f (int){cout<<"…D"<<endl;}
+    void f (int){cout<<"D::f()"<<endl;}
 };
 int main(){
     A *pA,a;
     B *pB, b;    C c;    D d;
     pA=&a;    pA->f(1);		//调用A::f
-    pB=&b;    pB->f(1);		//调用A::f
-    pB=&c;    pB->f(1);		//调用A::f
-    pB=&d;    pB->f(1);		//调用A::f
+    pB=&b;    pB->f(1);		//调用B::f
+    pB=&c;    pB->f(1);		//调用C::f
+    pB=&d;    pB->f(1);		//调用D::f
     system("pause");
     return 0;
 }