Compilare: main.cpp: In function 'void add_string()': main.cpp:121:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(sol.size()<k) ~~~~~~~~~~^~ main.cpp: In function 'int tolit(char)': main.cpp:23:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'char tochar(int)': main.cpp:32:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int who_beats(int)': main.cpp:41:1: warning: control reaches end of non-void function [-Wreturn-type] } ^