Compilare: user.cpp: In function ‘bigint operator+(const bigint&, const bigint&)’: user.cpp:26:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (r>0) { c.t[0]++; c.t[c.t[0]]=r; } ^ user.cpp: In function ‘bigint operator*(int, const bigint&)’: user.cpp:36:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (r>0) { c.t[0]++; c.t[c.t[0]]=r; } ^ user.cpp: In function ‘int main()’: user.cpp:41:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perm.in","r",stdin); ^ user.cpp:42:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perm.out","w",stdout); ^ user.cpp:43:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&k); ^