Compilare: user.cpp: In function ‘void add_to_a(char)’: user.cpp:17:11: warning: array subscript has type ‘char’ [-Wchar-subscripts] a[a[0]]=x; ^ user.cpp: In function ‘bool do_shit(int)’: user.cpp:24:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=strlen(b[k].a+1);i++) ^ user.cpp: In function ‘int main()’: user.cpp:36:17: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses] f>>b[i].a+1; ^