Compilare: user.cpp: In function ‘int get_first(int, int)’: user.cpp:54: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int doit(int)’: user.cpp:80: warning: comparison between signed and unsigned integer expressions user.cpp:89: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:106: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:107: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:108: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:110: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result