Compilare: user.cpp: In function ‘int main()’: user.cpp:22:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nmult.in","r",stdin); ^ user.cpp:23:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nmult.out","w",stdout); ^ user.cpp:25:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&k,&w); ^ user.cpp:36:29: warning: ‘c’ may be used uninitialized in this function [-Wmaybe-uninitialized] sol=1LL*a*rid_put((1LL*b*c)%mod,mod-2)%mod; ^ user.cpp:36:27: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] sol=1LL*a*rid_put((1LL*b*c)%mod,mod-2)%mod; ^ user.cpp:36:12: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized] sol=1LL*a*rid_put((1LL*b*c)%mod,mod-2)%mod; ^