Compilare: user.cpp: In function ‘std::string div(std::string)’: user.cpp:23:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.length(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:103:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i1 < s1.size() && i2 < s2.size()) { ^ user.cpp:103:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i1 < s1.size() && i2 < s2.size()) { ^