Compilare: user.cpp: In function ‘int main()’: user.cpp:90:36: warning: unused variable ‘prer’ [-Wunused-variable] int prel = Q[i - 1].fi.fi, prer = Q[i - 1].fi.se; ^ user.cpp:61:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pq.in","r",stdin); ^ user.cpp:62:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pq.out","w",stdout); ^ user.cpp:66:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i]); ^ user.cpp:78:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&Q[i].fi.fi,&Q[i].fi.se); ^