C + + shortage make namespace enum

Namespace

I wrote two namespaces with the same name function.

[email protected] tmp]# cat main.cpp #include <iostream>namespace space1{void fun (void) {std::cout<< " Space1 \ n ";}} namespace space2{void fun (void) {std::cout<< "Space2 \ n";}} int main (void) {fun (); return 0;} No namespace specified, error during compilation: [[email protected] tmp]# g++ main.cpp &&./a.out main.cpp:In function ' int main () ': main.cpp:22: Error: ' Fun ' is not declared in this scope[[email protected] tmp]#

Using a Namespace

[email protected] tmp]# cat main.cpp #include <iostream>namespace space1{void fun (void) {std::cout<< " Space1 \ n ";}} namespace space2{void fun (void) {std::cout<< "Space2 \ n";}} Using namespace Space1;int main (void) {fun (); return 0;} [Email protected] tmp]# g++ main.cpp &&/a.out space1 [[email protected] tmp]#

To specify namespaces manually:

[email protected] tmp]# cat main.cpp #include <iostream>namespace space1{void fun (void) {std::cout<< " Space1 \ n ";}} namespace space2{void fun (void) {std::cout<< "Space2 \ n";}} int main (void) {Space1::fun (); Space2::fun (); return 0;} [Email protected] tmp]# g++-wall main.cpp &&/a.out space1 space2 [[email protected] tmp]#

Enumeration

[[Email protected] tmp]# cat main.c# include <stdio.h>enum weekday  {sun,mon,tue,wed,thu,fri,sat} day; int main () { int k;printf ("input a  Number (0--6)   "), scanf ("%d ", &k);d ay= (enum weekday) K;switch (day)  { case sun:printf ( "sunday\n"); break;case mon:printf ("monday\n"); break;case tue:printf ("tuesday\n"); break;case wed :p rintf ("wednesday\n"); break;case thu:printf ("thursday\n"); break; case fri:printf ("friday\n"); break;case sat:printf ("satday\n"); break; default:printf ("input error\n"); break;}  return 0;}  [[email protected] tmp]# gcc main.c && ./a.out input a  number (0--6)  2tuesday[[email protected] tmp]# gcc main.c && . /a.out input a number (0--6)  0sunday[[email protected] tmp]#

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C + + shortage make namespace enum