Compilare: main.cpp: In function 'void read()': main.cpp:40:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a.size(); i++){ ~^~~~~~~~~ main.cpp:50:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a.size(); i++){ ~^~~~~~~~~ main.cpp:55:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=a.size(); i<b.size(); i++){ ~^~~~~~~~~