Compilare: main.cpp: In function 'void build1()': main.cpp:23:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 23 | while(ind < s1.size()) | ~~~~^~~~~~~~~~~ main.cpp: In function 'void build()': main.cpp:41:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 41 | while(ind < s2.size()) | ~~~~^~~~~~~~~~~