art.cpp: In function 'bool check(long long unsigned int)':
art.cpp:20:22: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
20 | for(register int i = 0; i <= 20; ++i){
| ^
art.cpp: In function 'int main()':
art.cpp:30:22: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
30 | for(register int i = 1; i <= n; ++i){
| ^
art.cpp:33:22: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
33 | for(register int mask = 1; mask < (1LL << n); ++mask){
| ^~~~
art.cpp:33:37: warning: comparison of integer expressions of different signedness: 'long long unsigned int' and 'long long int' [-Wsign-compare]
33 | for(register int mask = 1; mask < (1LL << n); ++mask){
| ~~~~~^~~~~~~~~~~~
art.cpp:38:26: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
38 | for(register int i = 1; i <= n; ++i){
| ^