Compilare: main.cpp: In function 'int main()': main.cpp:53:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a.size(); i++) ~~^~~~~~~~~~ main.cpp:62:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = a.size(); i < b.size(); i++) ~~^~~~~~~~~~ main.cpp:80:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < a.size(); i++) ~~^~~~~~~~~~ main.cpp:92:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = a.size(); i < b.size(); i++) ~~^~~~~~~~~~