C++模板编程 - 第九章 模板中的名称

 1 int x;
 2 
 3 class B
 4 {
 5 public:
 6     int i;
 7 };
 8 
 9 class D: public B
10 {
11 };
12 
13 void f(D* pd)
14 {
15     pd->i=3;    //ok
16     D::x=2;    // wrong, obviously
17 }
18 
19 ==================================================
20 
21 extern int count; // 1
22 
23 int lookup(int count) // 2
24 {
25     if(count<0)
26     {
27         int count =1; // 3
28         lookup(count); // 3
29     }
30     return count+::count; // 1+2
31 }
32 
33 ==================================================
34 
35 // a tricky one
36 template<typename T>
37 inline T const & max(const T & a, const T & b)
38 {
39     return a<b?b:a；
40 }
41 
42 namespace BigMath
43 {
44     class BigNumber
45     {
46         bool operator<(const BigNumber &, const BigNumber &);
47     };
48 }
49 
50 using BigMath::BigNumber;
51 
52 void g(const BigNumber & a, const BigNumber & b)
53 {
54     BigNumber x = max(a, b);    // max needs to know namespace BigMath
55 }

1 X<1>(0) == (X<1) > 0?

1 class X
2 {
3     ...
4 };
5 
6 List<::X> many_X;     // Noooooo! <: is a digraph which is [
7 List< ::X> some_X;    // Good