/in/foo.cc: In function 'int main(int, const char**)':
/in/foo.cc:25:10: warning: unused variable 'a' [-Wunused-variable]
     char a[2];
          ^
/in/foo.cc:26:10: warning: unused variable 'b' [-Wunused-variable]
     char b[2];
          ^
/in/foo.cc:27:10: warning: unused variable 'c' [-Wunused-variable]
     char c[4];
          ^