/in/foo.c:2:1: error: unknown type name 'using'
 using namespace std;
 ^~~~~
/in/foo.c:2:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'std'
 using namespace std;
                 ^~~
/in/foo.c: In function 'main':
/in/foo.c:27:4: error: expected ';' before 'break'
    break;
    ^~~~~
/in/foo.c:36:4: error: expected ';' before 'break'
    break;
    ^~~~~
/in/foo.c:43:10: error: stray '\357' in program
   case 11：
          ^
/in/foo.c:43:11: error: stray '\274' in program
   case 11：
           ^
/in/foo.c:43:12: error: stray '\232' in program
   case 11：
            ^
/in/foo.c:44:4: error: expected ':' or '...' before 'printf'
    printf("30");
    ^~~~~~
/in/foo.c:50:1: error: expected declaration or statement at end of input
 }
 ^