Alternately you could echo the input back to them and have them confirm their own typing.
Enter in a positive integer: -4
You typed "4294967292" is that correct? y/n N
Enter a positive integer:...
Type: Posts; User: whiteflags
Alternately you could echo the input back to them and have them confirm their own typing.
Enter in a positive integer: -4
You typed "4294967292" is that correct? y/n N
Enter a positive integer:...