Compilare: user.cpp: In function ‘void solve()’: user.cpp:37: warning: comparison between signed and unsigned integer expressions user.cpp:41: warning: comparison between signed and unsigned integer expressions user.cpp:46: warning: comparison between signed and unsigned integer expressions user.cpp:21: warning: unused variable ‘k’ user.cpp:21: warning: unused variable ‘nt’ user.cpp: In function ‘void read_data()’: user.cpp:64: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:68: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘int main()’: user.cpp:84: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:85: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result