Block users from typing non-digits CIN [C++]

Is there a way, using CIN, to block users from entering non-digit characters?
For example - I am prompting for the user to enter the Width of a box, obvious the response "abc" is not going to work ... aside from validating (getline(...) and return an error message) is there a way to simply block the user from entering it? So that hitting "a" just doesn't output anything for that CIN?

Any help would be much appreciated.
Thanks,

try this way:

int myx;
while(cin >> myx){
cout << "not a number";
}


best regards