/in/foo.cc: In function 'bool test(int, int, int, int)':
/in/foo.cc:11:13: error: 'strrev' was not declared in this scope
     strrev(x);
             ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:24:39: error: 'strrev' was not declared in this scope
             printf("%s\n",strrev(mw[i]));
                                       ^