Compilare: user.cpp: In function ‘void PushNumber(int)’: user.cpp:54:9: warning: unused variable ‘backup’ [-Wunused-variable] int backup = number; ^ user.cpp: In function ‘void Read()’: user.cpp:80:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &n); ^ user.cpp:84:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &tmp); ^