Compilare: main.cpp: In function 'void mask(std::string)': main.cpp:12:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 12 | for(int i = 0; i < s.size(); i ++) | ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:50:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for(int i = len; i < s.size(); i ++) | ~~^~~~~~~~~~ main.cpp:50:22: warning: 'len' may be used uninitialized [-Wmaybe-uninitialized] 50 | for(int i = len; i < s.size(); i ++) | ^ main.cpp:29:9: note: 'len' was declared here 29 | int len, cnt = 0; | ^~~