命名空间的问题

[fansedes]

在MFC下怎么使用命名空间，好象很玄妙的

[I_Love_CPP]

The C++ language provides a single global namespace. This can cause problems with global name clashes. For instance, consider these two C++ header files:

char func(char);
class String { ... };

// somelib.h
class String { ... };
With these definitions, it is impossible to use both header files in a single program; the String classes will clash.

A namespace is a declarative region that attaches an additional identifier to any names declared inside it. The additional identifier makes it less likely that a name will conflict with names declared elsewhere in the program. It is possible to use the same name in separate namespaces without conflict even if the names appear in the same translation unit. As long as they appear in separate namespaces, each name will be unique because of the addition of the namespace identifier. For example:

namespace one
{
char func(char);
class String { ... };
}

// somelib.h
namespace SomeLib
{
class String { ... };
}
Now the class names will not clash because they become one::String and SomeLib::String, respectively.

Declarations in the file scope of a translation unit, outside all namespaces, are still members of the global namespace.

[pomelowu]

不玄妙，定义了Namespace之后（如上），用using关键字就行了
using namespace std; // C++ 标准命名空间。

[bobob]

名字空间可比不同进程的地址空间,互相之间是独立的，不同进程的同一个地址实际指的位置不同,不同名字空间相同的变量名字意义也不同

简单讲,就是个变量加一个前缀

[qufan]

using 就可以了

[iamltq]

用法就象using namespace std; 一样，不同的命名空间，只要置换空间名字即可....

[fansedes]

这个我也知道，但是命名空间内的类使用了DECLARE_XXXXXX就编译不过了

[pomelowu]

MFC和标CPP是有兼容性问题的。

[legendhui]

xx

[oyljerry]

using namespace std;
就可以使用定义好的命名空间了，不过MFC与C++有时候有冲突