On 18/07/2010 12:27, Aaron Lewis wrote: > Hi, > how can i determine the maximum size of `double' without printing out > DOUBLE_MAX ? > > And what about the precision of a `double' , anyone give a try ? > > Google ain't giving much information , i just can't figure out , it's > very funny coding , isn't it ? >
Kinda off-topic for here but whatever... Assuming 64-bit double, it has a mantissa of 52 bits and an exponent of 11 bits. If the mantissa is all-ones, that will give a significant of 2-2^(-52). The exponent cannot be all-ones (an all-ones exponent means infinity or NaN), so the largest exponent is 2^11-2 = 2046, minus bias (1023), it gives a maximum effective exponent of 1023, so that would give a value of (2-2^(-52))*2^(1023) = 2^1024 - 2^971, roughly 10^308. What do you mean by "precision"? Firas
