Compilare: user.cpp: In function ‘void read()’: user.cpp:13: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void expand(int)’: user.cpp:30: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void check1(int)’: user.cpp:39: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void check2(int)’: user.cpp:57: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:92: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:93: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result