Compilare: user.cpp: In function ‘int main()’: user.cpp:118:19: warning: unused variable ‘cnt’ [-Wunused-variable] register int t, cnt, to; ^ user.cpp:118:24: warning: unused variable ‘to’ [-Wunused-variable] register int t, cnt, to; ^ user.cpp:89:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( FILE_IN, "r", stdin ); ^ user.cpp:90:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( FILE_OUT, "w", stdout ); ^ user.cpp:116:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &N); ^ user.cpp:121:29: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(S, sizeof(S), stdin); ^