Compilare: user.cpp: In function ‘int main()’: user.cpp:96:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( j = 0; j < pn; ++j) { ^ user.cpp:110:19: warning: unused variable ‘cnt’ [-Wunused-variable] register int t, cnt, to; ^ user.cpp:110:24: warning: unused variable ‘to’ [-Wunused-variable] register int t, cnt, to; ^ user.cpp:86:32: 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:87:34: 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:90:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &T); ^ user.cpp:108:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^