Compilare: main.cpp: In function 'int main()': main.cpp:60:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < strlen(s); i++) ~~^~~~~~~~~~~ main.cpp:85:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < strlen(s) && (s[i] >= '0' && s[i] <= '9')) ~~^~~~~~~~~~~