Compilare: user.cpp: In function ‘int read(int&)’: user.cpp:21:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(ch,bsize,1,stdin); ^ user.cpp:31:32: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(ch,bsize,1,stdin); ^ user.cpp:38:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(ch,bsize,1,stdin); ^ user.cpp: In function ‘int main()’: user.cpp:52:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("ciclueuler.in","r",stdin); ^ user.cpp:53:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("ciclueuler.out","w",stdout); ^ user.cpp:54:29: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread (ch,bsize,1,stdin); ^