How do I check if input is an integer/string?

Question

My problem here is I don\'t know how to insert a rule wherein if a user inputted a number on the string, it will cout a warning saying it\'s not valid, same wit

Answer 1

    cout << "\n Enter number : ";
    cin >> ch;
    while (!cin) {
        cout << "\n ERROR, enter a number" ;
        cin.clear();
        cin.ignore(256,'\n');
        cin >> ch;
    }