Operators in namespaces

Consider the binary operator @, if x is of type x, and y is of type Y,[email protected] will be parsed as follows:

--If X is a class, query as a member function of x or a member function of a base class of x [email protected].

--in the context of [email protected], check the [email protected] statement.

--if x is defined in namespace n, query [email protected] declaration in N.

--in the definition of Y in the namespace m, in the M-Cha village [email protected] statement.

1#include <iostream>2 using namespacestd;3 4 classX {5  Public:6     void operator+(int) {7cout <<"From class X"<<Endl;8     }9 };Ten  One intMain () { A x x; -X +1;//From class X -  the     return 0; -}

For Item 1

1#include <iostream>2 using namespacestd;3 4 classX {5  Public:6 };7 8 classY {9  Public:Ten }; One  A  - intMain () { - x x; the y y; -  -     void operator+ (x& X, y&y); -  +x + y;//From function -  +     return 0; A } at  - void operator+ (x& X, y&y) { -cout <<"From function"<<Endl; -}

For Item 2

1#include <iostream>2 using namespacestd;3 4 namespaceNX {5     classX {6      Public:7         /*void operator+ (int) {8 cout << "from class X" << Endl;9         }*/Ten     }; One  A     void operator+ (x& X,int) { -cout <<"Form namespace NX"<<Endl; -     } the } -  - intMain () { - nx::x X; +X +1;//From namespace NX -  +     return 0; A}

For Item 3

1#include <iostream>2 using namespacestd;3 4 classX {5  Public:6 };7 8 namespaceNY {9     classY {Ten      Public: One     }; A  -     void operator+ (x& X, y&y) { -cout <<"From namespace NY"<<Endl; the     } - } -  - intMain () { + x x; - ny::y Y; +  Ax + y;//From namespace NY at  -     return 0; -}

For Item 4

Reference: TC++PL P237

Operators in namespaces