Compilare: user.cpp: In function ‘void Read(int&)’: user.cpp:16:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] for (fread(C, 1, 1, rfile); C[0] < '0' || C[0] > '9';fread(C, 1, 1, rfile)) ; ^ user.cpp:16:5: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] for (fread(C, 1, 1, rfile); C[0] < '0' || C[0] > '9';fread(C, 1, 1, rfile)) ; ^ user.cpp:17:5: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] for (; C[0] >= '0' && C[0] <= '9'; fread(C, 1, 1, rfile)) ^