Compilare: main.cpp: In function 'int main()': main.cpp:25:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 25 | for (i=0;i<s.size();i++) | ~^~~~~~~~~ main.cpp:19:13: warning: unused variable 'n' [-Wunused-variable] 19 | int cer,n,i,col,row; | ^