Compilare: user.cpp: In function ‘int main()’: user.cpp:3:97: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int n,v1[u],v2[u],sol=-1,ct=0,i;int main(){freopen("mincinosi.in","r",stdin);freopen("mincinosi.out","w",stdout);scanf("%d",&n);for(i=1;i<=n;i++){scanf("%d",&v1[i]);v2[v1[i]]++;}for(i=0;i<=n;i++)if((i+v2[i])==n){sol=i;break;}printf("%d\n",v2[sol]);for(i=1;i<=n;i++)if(v1[i]==sol)printf("%d\n",i);} ^ user.cpp:3:133: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int n,v1[u],v2[u],sol=-1,ct=0,i;int main(){freopen("mincinosi.in","r",stdin);freopen("mincinosi.out","w",stdout);scanf("%d",&n);for(i=1;i<=n;i++){scanf("%d",&v1[i]);v2[v1[i]]++;}for(i=0;i<=n;i++)if((i+v2[i])==n){sol=i;break;}printf("%d\n",v2[sol]);for(i=1;i<=n;i++)if(v1[i]==sol)printf("%d\n",i);} ^ user.cpp:3:148: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int n,v1[u],v2[u],sol=-1,ct=0,i;int main(){freopen("mincinosi.in","r",stdin);freopen("mincinosi.out","w",stdout);scanf("%d",&n);for(i=1;i<=n;i++){scanf("%d",&v1[i]);v2[v1[i]]++;}for(i=0;i<=n;i++)if((i+v2[i])==n){sol=i;break;}printf("%d\n",v2[sol]);for(i=1;i<=n;i++)if(v1[i]==sol)printf("%d\n",i);} ^ user.cpp:3:185: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] using namespace std;int n,v1[u],v2[u],sol=-1,ct=0,i;int main(){freopen("mincinosi.in","r",stdin);freopen("mincinosi.out","w",stdout);scanf("%d",&n);for(i=1;i<=n;i++){scanf("%d",&v1[i]);v2[v1[i]]++;}for(i=0;i<=n;i++)if((i+v2[i])==n){sol=i;break;}printf("%d\n",v2[sol]);for(i=1;i<=n;i++)if(v1[i]==sol)printf("%d\n",i);} ^