将浮点数用于计数器-有问题吗？

Question

The code I'm looking at uses a golang float64 as a counter, does this pose a problem with loss of accuracy at some point? Specifically, are all integers represented in the range covered by float64? If not, where do I start running into problems? When do I run out of contiguous integers?

In case you're wondering, the reason for using a float64 as a counter is because it's part of a []float64 that holds many metrics that are not integers.

Answer 1

The golang specification says, "float64 is the set of all IEEE-754 64-bit floating-point numbers." which is commonly known as double precision numbers,

http://en.wikipedia.org/wiki/Double-precision_floating-point_format

You can read all of its glory details if interested, but to answer your question, quote,

"...next range, from 2⁵³ to 2⁵⁴, everything is multiplied by 2..."

So if you want to use it as counters, i.e. positive integers, you won't have problem until 2⁵³=9,007,199,254,740,992.