// Computing square with repeating and input control
#include<iostream>
using namespace std;
int main()
{
    int ok;
    do
    {
        double valnum;
        cout << "Input number: ";
        cin >> valnum;
        if (cin.good())
			cout << "Number " << valnum << " squared is " << valnum*valnum << endl;
        else
        {
            cin.clear();
            cin.ignore(256,'\n');
            cout << "Input error -- number required." << endl;
        }
        cout << " Continue (1) or close (0)?" << endl;
        cin >> ok;
    } while (ok == 1);
}