| The result is double precision. The smallest double is 2^-1022 = 10^-307. The probability of reaching a number between 0 and 10^-307 from a perfect uniform distribution would be so small that it would never happen if all the computers in the world did nothing but generating random numbers until doomsday!!! You have a choice between the resolutions 2^-32, 2^-52, and 2^-63 = 10^-19. That's more than enough for any application you could ever think of. I think you are confusing range and resolution. The range of floating point numbers is defined by the minimum/maximum exponent. The resolution is defined by the maximum number of decimals. A double can distinguish between 0 and 10^-307, but not between 1 and 1+10^-307. | 
Generate ALL float numbers in RNG? new - Hangzai Luo - 2004-06-16
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