Compilare: main.cpp: In function 'int main()': main.cpp:15:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=a.size()+1;i++) ~^~~~~~~~~~~~ main.cpp:17:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a.size();i++) ~^~~~~~~~~ main.cpp:22:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a.size();i++) ~^~~~~~~~~ main.cpp:32:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<b.size();i++) ~^~~~~~~~~