Compilare: main.cpp: In function 'int main()': main.cpp:19:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i<s.length(); i++) ~^~~~~~~~~~~ main.cpp:25:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s[i] == ' ' && i<s.length()) ~^~~~~~~~~~~ main.cpp:27:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while('0' <= s[i] && '9' >= s[i] && i<s.length()) ~^~~~~~~~~~~ main.cpp:41:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s[i] >= 'a' && s[i] <= 'z' && i<s.length()) ~^~~~~~~~~~~ main.cpp:49:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while('0' <= s[i] && '9' >= s[i] && i<s.length()) ~^~~~~~~~~~~