Compilare: user.cpp: In function ‘int main()’: user.cpp:45:8: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses] fin>>a+1>>b+1; ^ user.cpp:45:13: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses] fin>>a+1>>b+1; ^ user.cpp:57:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] j=pref[n]; ^