Compilare: user.cpp: In function ‘void read()’: user.cpp:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve()’: user.cpp:40: warning: comparison between signed and unsigned integer expressions user.cpp:53: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:86: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:87: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:88: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result