Compilare: main.cpp: In function 'int main()': main.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1;i<strlen(a);i++) { ~^~~~~~~~~~ main.cpp:46:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int o=0;o<v.size();o++) { ~^~~~~~~~~