A list of practical projects that anyone can solve in any programming language

Re:A list of practical projects that anyone can solve in any... by computerphage on Wednesday November 21, 2018 @03:32AM (#18501077)

There are simple math formulas that approximate pi. You can look one up and run it to the right number of digits. It would be hard without Google, but most programmers should be able to do it with Google so that they don't need to figure out any of the math.

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by leni536 on Wednesday November 21, 2018 @03:52AM (#18501148)

You need to use an arbitrary precision math library, I don't know how hard to use those. Those formulas have a hard limit in precision for standard floating point types.

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by dhartmei on Wednesday November 21, 2018 @04:00AM (#18501193)

You don't need arbitrary precision, use a spigot https://en.wikipedia.org/wiki/Pi#Spigot_algorithms

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by leni536 on Wednesday November 21, 2018 @05:15AM (#18501489)

I took a look at a spigot algorithm[1]. I still think it needs arbitrary precision arithmetics but maybe I miss something obvious.

[1] https://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%9...

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by dhartmei on Wednesday November 21, 2018 @05:21AM (#18501508)

Here's an example if you want to try http://www.benzedrine.ch/pi-spigot.c

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by leni536 on Wednesday November 21, 2018 @05:33AM (#18501565)

This doesn't look like a spigot algorithm. It has a link in the comments[1], it calculates the digits of PI from the beginning. The code you linked seems to implement the exact same algorithm.

I don't fully comprehend the code still, but the SCALE parameter suggest that it handles the elements of the array as a fixed point representation of real numbers. I wonder if it's correct for large number of digits.

[1] http://www.codecodex.com/wiki/Calculate_digits_of_pi#C

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by ajuc on Wednesday November 21, 2018 @05:07AM (#18501452)

Wow, this blew my mind. And it's so simple, too.

    def nthHexDigitOfPI(n):
        return 4/(8*n+1) - 2/(8*n+4) - 1/(8*n+5) - 1/(8*n+6)

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by leni536 on Wednesday November 21, 2018 @05:17AM (#18501492)

What you wrote just returns 0 for a large enough n.

[ Parent | on HN ]

Re:A list of practical projects that anyone can solve in any... by ajuc on Wednesday November 21, 2018 @05:40AM (#18501607)

Serves me right for stopping the reading on the first line :)

[ Parent | on HN ]