Compilare: user.cpp: In function ‘int bell()’: user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp:24: warning: unused variable ‘ok’ user.cpp: In function ‘int main()’: user.cpp:63: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:66: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result