Compilare: user.cpp: In function ‘int main()’: user.cpp:83:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(f[j] < v[j].size()) ^ user.cpp: In function ‘char gchar()’: user.cpp:22:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, buffer, 1, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:67:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bignumber.in", "r", stdin); ^ user.cpp:68:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bignumber.out", "w", stdout); ^