Compilare: main.cpp: In function 'int main()': main.cpp:55:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= a.size(); i++) { ~~^~~~~~~~~~~ main.cpp:59:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= b.size(); i++) { ~~^~~~~~~~~~~ main.cpp:63:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i < a.size()) { ~~^~~~~~~~~~