Compilare: main.cpp: In function 'int main()': main.cpp:69:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<a.size();++i) ~^~~~~~~~~ main.cpp:75:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1;i<b.size();++i) ~^~~~~~~~~ main.cpp:91:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<pos.size();++i) ~^~~~~~~~~~~