maxnat

#maxnat

##Syntax maxnat : nat

##Description The maxnat function is used to determine the largest natural number that can be used in a program.

##Example This program outputs the maximum natural number.

    put "The largest natural number that can be used is ", maxnat

##Details In current implementations, natural numbers are stored in 4 bytes, i.e., 32 bits. This determines the maximum natural number, which is 2**32 - 2, equaling 4294967294.

In four bytes it is possible to represent one more value, namely, 2**32 - 1 = 4294967295. This extra value is used in Turing to represent the uninitialized natural number. Although it can be computed, any attempt to assign it to a nat variable is detected as an overflow. You can use this extra value by using the nat4 type instead of nat, but this type has no initialization checking.

##See also maxint.html and minnat.html.

See also predefined unit limitsmodule.html.