Compilare: user.cpp: In function ‘bool num(char*)’: user.cpp:55:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] int r = val[*a]; ^ user.cpp: In function ‘int main()’: user.cpp:90:8: warning: unused variable ‘flag’ [-Wunused-variable] bool flag; ^ user.cpp:92:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d\n", &t); ^