Division of not so little numbers

Question

Write a program or function that takes in positive integers a, b and c, and prints or returns a/b to c decimal places, using the operations +-*/% [add, subtract, multiply, divide, modulate] on the positive integers: you can use all that your language allows, but not on floating point numbers. The range of a,b,c would be the range allowed for unsigned integers in your language. The number result will be truncated to the last digit to print (so no round).

This means that if your language does not have an integer type (only float), you can participate by using these float numbers as positive integers only. The clue of this exercise it would be to write the function that find the digits in a float point division, using only the operation +-*/% on [unsigned] integers.

Examples

• print(1,2,1) would print 0.5
• print(1,2,2) would print 0.50
• print(13,7,27) would print 1.857142857142857142857142857
• print(2,3,1) would print 0.6
• print(4,5,7) would print 0.8000000
• print(4,5,1) would print 0.8
• print(9999,23,1) would print 434.7
• print(12345613,2321,89) would print if your Language has 32 bit unsigned 5319.09220163722533390779836277466609220163722533390779836277466609220163722533390779836277466

The shortest code in bytes wins. I'm sorry if this appear not clear... I don't know languages too, not remember words well... It is better to have one link to Ideone.com or some other place for easily try the answer especially for to test some input different from proposed.

Answer 1

05AB1E, 17 13 11 19 14 bytes

Input in the form b, a, c.
Saved 5 bytes thanks to Grimy.

‰`¹+I°*¹÷¦'.sJ

Try it online!

Answer 2

Haskell, 87 bytes

(a#b)c|s<-show$div(a*10^c)b,l<-length s-c,(h,t)<-splitAt l s=['0'|l<1]++h++['.'|c>0]++t

Usage example: (13#7)27 -> "1.857142857142857142857142857".

23 bytes to handle the c==0 case and using a leading zero instead of things like .5.

How it works: multiply a with 10^c, divide by b, turn into a string, split where the . must be inserted, join both parts with a . in-between and fix the edge cases.

Answer 3

Perl 6,  58 57 55  48 bytes

{(($^a.FatRat/$^b*10**$^c).Int.FatRat/10**$c).base(10,$c)}

{(Int($^a.FatRat/$^b*10**$^c).FatRat/10**$c).base(10,$c)}

{base Int($^a.FatRat/$^b*10**$^c).FatRat/10**$c: 10,$c}

{base ($^a*10**$^c div$^b).FatRat/10**$c: 10,$c}

What is fairly annoying is that it could be shortened to just {($^a.FatRat/$^b).base(10,$^c)} if it was allowed to round to the nearest value.

Explanation:

# bare block lambda with 3 placeholder parameters ｢$^a｣, ｢$^b｣ and ｢$^c｣
{
  (
    (

      # create an Int containing all of the digits we care about
      $^a * 10 ** $^c div $^b

    ).FatRat / 10**$c  # turn it into a Rational

  ).base( 10, $c )     # force it to display ｢$c｣ digits after the decimal point
}

Answer 4

Perl, 55 bytes

Includes +3 for -p

Give a and b on one line on STDIN, c on the next

division.pl
1 26
38
^D

division.pl:

#!/usr/bin/perl -p
eval'$\.=($_/$&|0)."."x!$\;$_=$_%$&.0;'x(/ .*/+<>)}{

the $_/$& is a bit arguable. I Actually want an integer division there but perl doesn't have that without loading special modules. So it's temporarily a non-integer which I then immediately truncate (using |0) so I end up with the integer an integer division would give. It could be rewritten as ($_-$_%$&)/$& in order to not even temporarily have a non-integer value (it would internally still be a float though)

Answer 5

JavaScript (ES6), 55 50 bytes

f=(a,b,c,d=".")=>~c?(a/b|0)+d+f(a%b*10,b,c-1,""):d

(a/b|0) performs float division but immediately casts to an integer. Please let me know if this is not allowed.

Answer 6

PHP, 187 Bytes

works with strings for the numerator which can be int values greater then PHP_INT_MAX

list(,$n,$d,$c)=$argv;$a=str_split($n);while($a){$n.=array_shift($a);if($n>=$d||$r)$n-=$d*$r[]=$n/$d^0;}if(!$r)$r[]=0;if($c)$r[]=".";while($c--){$n*=10;$n-=$d*$r[]=$n/$d^0;}echo join($r);

I have no other chance then 13/7 is shorten to 1.8571428571429 and I reach so not the test case with 27 decimal places

This way 36 Bytes is not allowed

<?=bcdiv(($z=$argv)[1],$z[2],$z[3]);

Answer 7

Pyth - 21 19 18 16 14 bytes

Will be looking over the input format, that can prolly save a bunch.

j\.c`/*E^TQE]_

Test Suite. (P.S. the 27 one doesn't finish online, so I did 10 instead).

Answer 8

JavaScript (ES6),  64  62 59 bytes

Saved 2 bytes thanks to ETHproductions.

The included division always results in an integer.

f=(a,b,n,s)=>~n?f((q=(a-a%b)/b,a%b*10),b,n-1,s?s+q:q+'.'):s

console.log(f(13,7,27))

Answer 9

Java 7, 105 bytes

import java.math.*;String c(int...a){return new BigDecimal(a[0]).divide(new BigDecimal(a[1]),a[2],3)+"";}

Ungolfed & test code:

Try it here.

import java.math.*;
class M{
  static String c(int... a){
    return new BigDecimal(a[0]).divide(new BigDecimal(a[1]), a[2], 3)+"";
  }

  public static void main(String[] a){
    System.out.println(c(1, 2, 1));
    System.out.println(c(1, 2, 2));
    System.out.println(c(13, 7, 27));
    System.out.println(c(2, 3, 1));
    System.out.println(c(4, 5, 7));
    System.out.println(c(4, 5, 0));
    System.out.println(c(9999, 23, 0));
    System.out.println(c(12345613, 2321, 89));
  }
}

Output:

0.5
0.50
1.857142857142857142857142857
0.6
0.8000000
0
434
5319.09220163722533390779836277466609220163722533390779836277466609220163722533390779836277466

Answer 10

Ruby, 67 bytes

->(a,b,c){('0'+(a*10**c/b).to_s).gsub(/^0*(.+)(.{#{c}})$/,'\1.\2')}

if I make it a function to execute the test cases above

def print(a,b,c); ('0'+(a*10**c/b).to_s).gsub(/^0*(.+)(.{#{c}})$/, '\1.\2'); end
 => :print 
print(1,2,1)   # would print 0.5
 => "0.5" 
print(1,2,2)   # would print 0.50
 => "0.50" 
print(13,7,27) # would print 1.857142857142857142857142857
 => "1.857142857142857142857142857" 
print(2,3,1)   # would print 0.6
 => "0.6" 
print(4,5,7)   # would print 0.8000000
 => "0.8000000" 
print(4,5,1)   # would print 0.8
 => "0.8" 
print(9999,23,1) # would print 434.7
 => "434.7" 
print(12345613,2321,89) # would print if your Language has 32 bit unsigned 5319.09220163722533390779836277466609220163722533390779836277466609220163722533390779836277466
 => "5319.09220163722533390779836277466609220163722533390779836277466609220163722533390779836277466" 
"('0'+(a*10**c/b).to_s).gsub(/^0*(.+)(.{#{c}})$/, '\1.\2')".length
 => 52 

Answer 11

Racket 203 bytes

(let*((s(~r(/ a b)#:precision c))(sl(string-split s "."))(s2(list-ref sl 1))(n(string-length s2)))
(if(< n c)(begin(for((i(- c n)))(set! s2(string-append s2 "0")))(string-append(list-ref sl 0)"."s2))s))

Ungolfed:

(define (f a b c)
  (let* ((s (~r(/ a b)#:precision c))
         (sl (string-split s "."))
         (s2 (list-ref sl 1))
         (n (string-length s2)))
    (if (< n c)
        (begin 
          (for ((i (- c n)))
            (set! s2 (string-append s2 "0")))
          (string-append (list-ref sl 0) "." s2))
        s )))

Usage:

(f 7 5 3)
(f 1 2 1) 
(f 1 2 2) 
(f 13 7 27)

Output:

"1.400"
"0.5"
"0.50"
"1.857142857142857142857142857"

Other method (not valid answer here):

(real->decimal-string(/ a b)c)

Answer 12

q, 196 bytes

w:{((x 0)div 10;1+x 1)}/[{0<x 0};(a;0)]1;{s:x 0;m:x 2;r:(10*x 1)+$[m<0;{x*10}/[-1*m;a];{x div 10}/[m;a]]mod 10;d:1#.Q.s r div b;($[m=-1;s,".",d;$[s~,:'["0"];d;s,d]];r mod b;m-1)}/[c+w;("";0;w-1)]0

To run: set a, b, c first.

Answer 13

Rust, 114 bytes

fn print(mut a:u32,b:u32,c:u32){let mut p=||{print!("{}",a/b);a=a%b*10};p();if c>0{print!(".")}for _ in 0..c{p()}}

test code:

fn main() {
    print(1, 2, 1);    println!(""); // should print 0.5
    print(1, 2, 2);    println!(""); // should print 0.50
    print(13, 7, 27);  println!(""); // should print 1.857142857142857142857142857
    print(2, 3, 1);    println!(""); // should print 0.6
    print(4, 5, 7);    println!(""); // should print 0.8000000
    print(4, 5, 0);    println!(""); // should print 0
    print(9999, 23, 0);println!(""); // should print 434
    print(12345613,2321,89); println!("\n");  // 5319.09220163722533390779836277466609220163722533390779836277466609220163722533390779836277466
}

Answer 14

PHP, 89 bytes

list(,$a,$b,$c)=$argv;for($o=intdiv($a,$b).'.';$c--;)$o.=intdiv($a=10*($a%$b),$b);echo$o;

intdiv() is introduced in php 7 so it requires that. php 7.1 would allow me to change the list() to [] and so would save 4 bytes.

use like:

php -r "list(,$a,$b,$c)=$argv;for($o=intdiv($a,$b).'.';$c--;)$o.=intdiv($a=10*($a%$b),$b);echo$o;" 1 2 1

Answer 15

C#, 126 bytes

(a,b,c)=>{var v=a*BigInteger.Parse("1"+new string('0',c))/b+"";return v.PadLeft(c+1,'0').Insert(Math.Max(1,v.Length-c),".");};

Full program with test cases:

using System;
using System.Numerics;

namespace DivisionOfNotSoLittleNumbers
{
    class Program
    {
        static void Main(string[] args)
        {
            Func<BigInteger,BigInteger,int,string>f= (a,b,c)=>{var v=a*BigInteger.Parse("1"+new string('0',c))/b+"";return v.PadLeft(c+1,'0').Insert(Math.Max(1,v.Length-c),".");};
            
            //test cases:
            Console.WriteLine(f(1,2,1));    //0.5
            Console.WriteLine(f(1,2,2));    //0.50
            Console.WriteLine(f(13,7,27));  //1.857142857142857142857142857
            Console.WriteLine(f(2,3,1));    //0.6
            Console.WriteLine(f(4,5,7));    //0.8000000
            Console.WriteLine(f(4,5,1));    //0.8
            Console.WriteLine(f(9999,23,1));    //434.7
            Console.WriteLine(f(12345613,2321,89)); //5319.09220163722533390779836277466609220163722533390779836277466609220163722533390779836277466
            Console.WriteLine(f(2,3,1));    //0.6
            Console.WriteLine(f(4,5,2));    //0.80
        }
    }
}

Integer division is implemented. Numbers of any size can be used, due to the BigInteger data type (the import System.Numerics is required). The digit-count parameter c is restricted to 2^31-1, however it should provide more than enough digits.

Answer 16

Groovy (78 77 42 Bytes)

{a,b,n->Eval.me(a+'.0g').divide(b, n, 1)}​

Explanation

Eval.me(a+'.0g'); - Convert from integer input to BigDecimal input. In groovy BigDecimal notation is double notation with an appended G or g. I could've also used the constructor new BigDecimal(it) but this saved a byte.
.divide(b, n, 1) - Divide by b with n precision, rounding mode half-up.

Try it here: https://groovyconsole.appspot.com/script/5177545091710976

Answer 17

Batch, 122 bytes

@set/as=%1/%2,r=%1%%%2
@set s=%s%.
@for /l %%a in (1,1,%3)do @set/ad=r*10/%2,r=r*10%%%2&call set s=%%s%%%%d%%
@echo %s%

Answer 18

Mathematica, 50 bytes

StringInsert[ToString@Floor[10^# #2/#3],".",-#-1]&

Unnamed function of three arguments (which are ordered c, a, b to save a byte somewhere), which returns a string. It multiplies a/b by 10^c, takes the greatest integer function, then converts to a string and inserts a decimal point at the appropriate spot. Too bad the function names aren't shorter.

Answer 19

Python 3, 62 Bytes

a,b,c=map(int,input().split());print("{:.{1}f}".format(a/b,c))

Try It Here

*Note: repl.it uses an older ver of Python 3, which requires all field indices to be specified, meaning "{:.{1}f}" will be "{0:.{1}f}" instead, making it 63 bytes in repl.it

How to use

Enter all three values with spaces in-between. i.e. An input of 1 2 1 would give a result of 0.5

Explanation

input().split(): Gets user input and splits it into a list with a separator of (space)

a,b,c = map(int,XX): Maps the variables into the values specified by the user with an int type

"{:.{1}f}".format(a/b,c): Formats a string to display the division result and substitutes {1} with c to set the decimal place of the displayed string

print(XX): prints the string supplied

Answer 20

Python 3, 58 bytes

lambda a,b,c:(lambda s:s[:-c]+"."+s[-c:])(str(a*10**c//b))

Try it online!

This is precise to the specified number of decimals as long as a * 10 ** c isn't too large.

I tried Python 2 to shorten the str(...) to `...` but Python 2 inserts an L at the end if it's too large so checking for that would take way more bytes than it's worth.

Answer 21

Stax, 13 bytes

ä·oαì█↕▬AS¥é▼

Run and debug it

Arguments are accepted in c a b order.

Answer 22

C, 67 bytes

h(a,b,i){int j=!i;for(;printf(j++?"%u":"%u.",a/b),i--;a=10*(a%b));}

Try it online!

Some previous version I think had a bug in read memory out of assigned to the program...Thanks to ceilingcat and for all...