Compilare: main.cpp: In function 'void doSet(std::__cxx11::string&)': main.cpp:25:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < s.size() && isdigit(s[i])) { ~~^~~~~~~~~~ main.cpp:30:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < s.size() && isdigit(s[i])) { ~~^~~~~~~~~~ main.cpp:35:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < s.size() && isdigit(s[i])) { ~~^~~~~~~~~~ main.cpp: In function 'std::vector<int> intersect(std::vector<int>&, std::vector<int>&)': main.cpp:53:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < a.size() && j < b.size()) ~~^~~~~~~~~~ main.cpp:53:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < a.size() && j < b.size()) ~~^~~~~~~~~~ main.cpp: In function 'std::vector<int> merge(std::vector<int>&, std::vector<int>&)': main.cpp:72:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < a.size() && j < b.size()) ~~^~~~~~~~~~ main.cpp:72:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < a.size() && j < b.size()) ~~^~~~~~~~~~ main.cpp:91:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < a.size()) ~~^~~~~~~~~~ main.cpp:96:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < b.size()) ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:116:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); i++) ~~^~~~~~~~~~ main.cpp:148:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < expr.size(); i++) ~~^~~~~~~~~~~~~