Compilare: user.cpp: In function ‘void read(int&)’: user.cpp:28:45: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,1,BufferSize,stdin); ^ user.cpp:38:45: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,1,BufferSize,stdin); ^ user.cpp: In function ‘int main()’: user.cpp:47:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("knumere.in","r",stdin); ^ user.cpp:48:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("knumere.out","w",stdout); ^ user.cpp:49:37: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,1,BufferSize,stdin); ^ user.cpp: In function ‘void read(int&)’: user.cpp:41:5: warning: ‘c’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (c=='-') ^