Compilare: main.cpp: In function 'void bk(int)': main.cpp:13:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 13 | if(indi==a.size()){ | ~~~~^~~~~~~~~~ main.cpp:28:14: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 28 | if(a.size()-1==indi){ | ~~~~~~~~~~^~~~~~ main.cpp:51:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 51 | if(frmax>=(a.size()-indi)/2+1){ | ~~~~~^~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:82:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 82 | for(ij=0;ij<a.size();++ij){ | ~~^~~~~~~~~