Compilare: main.cpp: In function 'int main()': main.cpp:38:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 2, lung = 0; i < sir.size(); i++) ~~^~~~~~~~~~~~ main.cpp:51:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < sir.size(); i++) ~~^~~~~~~~~~~~ main.cpp:60:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 3; i < sir.size(); i++) ~~^~~~~~~~~~~~