Compilare: user.cpp: In function ‘void read()’: user.cpp:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void bf(int)’: user.cpp:43: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void prep()’: user.cpp:61: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:70: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:71: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result