Compilare: user.cpp: In function ‘int main()’: user.cpp:39:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (com < s[i-1].size() && com < s[i].size() && s[i-1][com] == s[i][com]) { ^ user.cpp:39:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (com < s[i-1].size() && com < s[i].size() && s[i-1][com] == s[i][com]) { ^