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digitalmars.D.learn - Why pow() won't go beyond 2^31?

reply Murilo <murilomiranda92 hotmail.com> writes:
I am using the function pow() from std.math but if I try pow(2, 
32) it returns 0, it doesn't compute beyond the maximum value of 
an int(2^31) and I am working with long. What should I do?
Nov 28 2018
next sibling parent Alex <sascha.orlov gmail.com> writes:
On Thursday, 29 November 2018 at 07:07:06 UTC, Murilo wrote:

 I am using the function pow() from std.math but if I try pow(2, 
 32) it returns 0, it doesn't compute beyond the maximum value 
 of an int(2^31) and I am working with long. What should I do?


what exactly is your input?

´´´
import std.stdio;
import std.experimental.all;

void main()
{
	long u = 2;
	assert(pow(u,32) == 4294967296);
	assert(pow(2UL,32) == 4294967296);
}
´´´
Nov 28 2018
prev sibling next sibling parent Daniel Kozak <kozzi11 gmail.com> writes:
On Thu, Nov 29, 2018 at 8:10 AM Murilo via Digitalmars-d-learn <
digitalmars-d-learn puremagic.com> wrote:


 I am using the function pow() from std.math but if I try pow(2,
 32) it returns 0, it doesn't compute beyond the maximum value of
 an int(2^31) and I am working with long. What should I do?


if you look at doc: https://dlang.org/phobos/std_math.html#.pow.2

you will see that return type is infered from pow arguments, so if both
arguments are int for example the return value would be int too
https://run.dlang.io/is/FMVJhY

so if you want to have long as output one of your args should be (u)long or
you can enforce that by
pow!long(2,32);

https://run.dlang.io/is/WlDfsE
Nov 29 2018
prev sibling parent Murilo <murilomiranda92 hotmail.com> writes:
Hi guys, thank you for helping me out here, there is this 
facebook group for the D language, here we can help and teach 
each other. It is called Programming in D. Please join. 
https://www.facebook.com/groups/662119670846705/?ref=bookmarks
Dec 09 2018