Compilare: main.cpp: In function 'bool verificare()': main.cpp:59:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(fr_size()!=v.size()) ~~~~~~~~~^~~~~~~~~~ main.cpp: In function 'bool factor()': main.cpp:126:12: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized] return val; ^~~