Compilare: user.cpp: In member function ‘void big_num::operator=(int)’: user.cpp:21: warning: array subscript has type ‘char’ user.cpp: In member function ‘void big_num::read()’: user.cpp:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In member function ‘void big_num::operator-=(const big_num&)’: user.cpp:65: warning: array subscript has type ‘char’ user.cpp: In function ‘int main()’: user.cpp:107: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:108: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:110: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result