设有程序
$ cat -n base2.cpp
1 #include <iostream>
2 using namespace std;
3 class Base
4 {
5 int x;
6 public:
7 Base(int i) {x=i;}
8 int getx() {return x;}
9 void disp() {cout<<"The value of x in Base is: "<<x<<endl;}
10 };
11 template <class T>
12 class Derived:public Base
13 {
14 T y;
15 public:
16 Derived(T a,int j):Base(j){y=a;}
17 T gety(){return y;}
18 void disp()
19 {cout<<"The value of y in Derived is : "<<y<<", and x in Derived is: "<<gety()<<endl;}
20 };
21 int main()
22 {
23 Base obj_B(888);
24 obj_B.disp();
25 Derived<int> obj_D1(1,2);
26 Derived<double> obj_D2(8.8,6);
27 Derived<char *> obj_D3("zrf",10);
28 Derived<char> obj_D4('=',20);
29 obj_D1.disp();
30 obj_D2.disp();
31 obj_D3.disp();
32 obj_D4.disp();
33
34 }
则其运行结果为：
$ ./base2
The value of x in Base is: 888
The value of y in Derived is : 1, and x in Derived is: 1
The value of y in Derived is : 8.8, and x in Derived is: 8.8
The value of y in Derived is : zrf, and x in Derived is: zrf
The value of y in Derived is : =, and x in Derived is: =
然后将template <class T>改为template <typename T>,重新编译，运行结果一样，这样就证明了class T等价于typename T
