Mucking around with numbers

/4 Comments/in /by

So, I was reading up on the Fibonacci sequence the other day, and wondered how long it would take CF to calculate the sequence to a couple of thousand steps, and also how long those numbers ended up becoming.

Consider the following loop:

<cfset n1 =0>
<cfset n2 =1>
<table>
<thead>
<tr><th>Row</th><th>No.</th><th>Length</th>
</thead>
<tbody>
<cfloop from="1" to="1000" index="i">
<cfset x = (n1 + n2)>
<cfoutput>
<tr><td>#i#</td><td>#len(numberformat(x))#</td><td>#numberformat(x)#</td></tr>
</cfoutput>
<cfset n1 = n2>
<cfset n2 = x>
</cfloop>
</tbody>
</table>

I immediately hit a few issues. One was scientific notation, which was solved by numberformat(), but the other issue I found was that if I tried to increase the number of loop iterations beyond 1475, I’d get an error simply stating ‘For input string: “I”‘

Removing the numberformat mask revealed 1.30698922376E+308 as the largest generated number in the sequence, with the remaining rows represented as ‘1.#INF’.

So, out of curiosity, does anyone know why? Is it simply that Java can’t handle larger integers?