iostream - How to use cin.fail() in c++ properly -

i'm writing program integer input user cin>>iusersel;. if user puts in letter, program goes infinite loop. tried prevent code below, program goes infinite loop , prints out "wrong! enter #!". how can fix program?

cin>>iusersel; while (ivalid == 1) {         if (cin.fail())         {                 cin.ignore();                 cout<<"wrong! enter #!"<<endl;                 cin>>iusersel;         }//closes if         else                 ivalid = 0; }//closes while 

i found information on @ correct way use cin.fail() , c++ cin.fail() question , didn't understand how use them fix issue.

after cin fails need clear error flag otherwise other input operation non op. clear error flags need call cin.clear(). code become

cin >> iusersel; while (ivalid == 1) {     if (cin.fail())     {         cin.clear(); // clears error flags         cin.ignore();         cout << "wrong! enter #!" << endl;         cin >> iusersel;     }//closes if     else         ivalid = 0; }//closes while 

i suggest change cin.ignore(); cin.ignore(numeric_limits<streamsize>::max(), '\n'); in case user enters more 1 letter.