I want to do an input check to the characters that the user enters .
The only permitted inputs are Integers , i.e. ,if the user enters a series
that has at least one Space (" ") or at least one character other than the digits 0-9
then the Input above is incorrect.
So why not do it with
In that way I get a string (str) , right ? but how can i check each and every character
in the string ? because the string is not a list ,and isn't an array .