Compilare: user.cpp: In function ‘void read()’: user.cpp:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:29: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void solve(int)’: user.cpp:58: warning: unused variable ‘j’ user.cpp: In function ‘void update(int)’: user.cpp:108: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void solve2(int)’: user.cpp:128: warning: unused variable ‘j’ user.cpp: In function ‘int main()’: user.cpp:197: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:198: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result