Compilare: main.cpp: In function 'int main()': main.cpp:33:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.sz-1; i++) ~~^~~~~~~~ main.cpp:38:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.sz; i++) ^ main.cpp:40:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.sz; i++) ^ main.cpp:42:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.sz; i++) ^