Code Golf: Banknote calculator

Question

This question was posted by a C beginner and it was an exercise to calculate, given a dollar value input by the user, the minimum number of bills (or banknotes, depending on your locale) needed to reach that dollar value.

So, if the user entered 93, the output would be:

$20 bills = 4
$10 bills = 1
$5 bills = 0
$1 bills = 3

Finally succumbing to the phenomenon (it's a slow day here), I thought this would be ripe for a game of Code Golf.

For fairness, the input prompt needs to be (note the "_" at the end is a space):

Enter a dollar amount:_

I think I've covered all the bases: no identical question, community wiki. I won't be offended if it gets shut down though - of course, I'll never be able to complain about these types of questions again, for fear of being labelled a hypocrite :-)

Okay, let's see what you can come up with. Here's a sample run:

Enter a dollar amount: 127
$20 bills = 6
$10 bills = 0
$5 bills = 1
$1 bills = 2

Answer 1

194 characters (with two lines, the #include and the rest combined on one line with leading spaces removed - formatted here for readability, though that's a relative term):

#include <stdio.h>
int main(void){
    int c,n;
    printf("Enter a dollar amount: ");scanf("%d",&c);
    for(n=20;n;n=(4600-6740*n+2213*n*n-73*n*n*n)/17100)
        {printf("$%d bills = %d\n",n,c/n);c=c%n;}
    return 0;
}

Answer 2

F#, 136 chars

Code-golf:

printf"Enter a dollar amount: ";Seq.fold(fun r b->printfn"$%d bills = %d"b (int(r/b));r%b)(System.Console.ReadLine()|>int)[20;10;5;1]

with whitespace added for readability:

printf "Enter a dollar amount: "
Seq.fold (fun r b->
            printfn "$%d bills = %d" b (int(r/b))
            r%b)
         (System.Console.ReadLine()|>int)
         [20;10;5;1]

Answer 3

Python, 83 chars

(or 84 depending on the line ending)

c=input("Enter a dollar amount: ")
for n in 20,10,5,1:print"$%d bills ="%n,c/n;c%=n

Joel's original attempt:

#!/usr/bin/python
c = int(input("Enter a dollar amount: "))
for n in [20,10,5,1]:
    print n,"bills =",c//n
    c = c % n

Answer 4

Perl 99 char

perl -MYAML -E'$d=<>;for(qw[100 50 20 10 5 1]){while(($t=$d-$_),$t>=0){$d=$t;$_{$_}++}}say Dump\%_'

Here is the code before I minimized it.

#! /opt/perl/bin/perl
use strict;
use warnings;
use 5.10.1;
use YAML;

my $dollar = <>;
my @bills = qw'100 50 20 10 5 1';

for( @bills ){
  my $t;
  while( ($t = $dollar - $_), $t >= 0 ){
    $dollar -= $_;
    $_{$_}++
  }
}

say Dump \%_;

If you insist on it printing a prompt, it goes up to 127

perl -MYAML -E'say"Enter a dollar amount:";$d=<>;for(qw[100 50 20 10 5 1]){while(($t=$d-$_),$t>=0){$d=$t;$_{$_}++}}say Dump\%_'

If you want to output the value as "$10 bills = 3", it goes up to 134

perl -E'say"Enter a dollar amount:";$d=<>;for(qw[100 50 20 10 5 1]){my$i;while(($t=$d-$_),$t>=0){$d=$t;$i++}say"\$$_ bills = $i"if$i}'

Answer 5

Now down to 121 characters in MATLAB:

>> p=@num2str;x=input('Enter a dollar amount: ');for c=[20 10 5 1],disp(['$' p(c) ' bills: ' p(floor(x/c))]);x=mod(x,c);end

----Prior Version----

134 characters (not counting the >> prompt) in Matlab:

>> p=@num2str;x=input('Enter a dollar amount: ');b=[20 10 5 1];for c=1:4,d=b(c);disp(['$' p(d) ' bills: ' p(floor(x/d))]);x=mod(x,d);end

Or, with four more characters, ...b=[100 20 10 5 1];for c=1:5... would be all about the Benjamins.

Answer 6

Perl, 89 chars

not counting EOL

print"Enter a dollar amount: ";$d=<>;printf"\$$_ bills = %d\n",$d/$_,$d%=$_ for 20,10,5,1

Perl 5.10, 87 chars

print"Enter a dollar amount: ";$d=<>;for(20,10,5,1){
say"\$$_ bills = ",int$d/$_;$d%=$_}

This might be non-qualifying since it will only run under perl -E or perl -M5.010 or with use 5.010; prepended, and if you count any of those it's longer than the other. :)

Answer 7

Well, I'll toss in a shorter C answer based on Pax's and call it a night, and let the golf gurus try to shorten it. 157 characters (note the very important space):

#include <stdio.h>
int main(){int n=40,c;printf("Enter a dollar amount: ");scanf("%d",&c);while(n/=2)if(n-2)printf("$%d bills = %d\n",n,c/n),c%=n;return 0;}

Formatted:

#include <stdio.h>
int main()
{
    int n = 40, c;
    printf("Enter a dollar amount: ");
    scanf("%d", &c);
    while(n /= 2)
        if(n - 2)
            printf("$%d bills = %d\n", n, c / n), c %= n;
    return 0;
}

Answer 8

c++ implementation, 193 not including space. might wanna add system("PAUSE") at the end of main to see output.

#include <iostream>
using namespace std;
void o(int a,int d)
{
    if(d!=2)
     if(a && d)
      cout << "$" << d << " bills = " << a/d << endl;
     else
      return;
    o(d!=2?a%d:a,d/2);
}
void main(){
    int n;
    cout << "Enter a dollar amount: ";
    cin >> n;
    o(n,20);
}

Answer 9

Lua

128 chars

Shown as two lines (broken at a space) to fit on the screen.

p=print p"Enter a dollar amount: "m=io.read()for _,i in pairs{20,10,5,1}do
x=math.modf(m/i)p("$"..i.." bills = "..x)m=m-x*i end

Answer 10

C#, 214

When formatted for Golf, the following C# is 214 characters in length:

using C = System.Console;
using System.Linq;
class P {
    static void Main() {
        C.Write("Enter a dollar amount: ");
        new[] { 20, 10, 5, 1 }.Aggregate(
            int.Parse(C.ReadLine()),
            (a, v) => { 
                C.Write("${0} bills = {1}\n", v, a / v);
                return a % v; 
            }
        );
    }
}

Thanks Andrew Shepherd!

Answer 11

Ruby, 97

$><<'Enter a dollar amount: '
n=gets.to_i
[20,10,5,1].map{|i|$><<"$%d bills = %d\n"%[i,n/i]
n%=i}

---

Would someone please do one of these for language-agnostic-but-not-perl? :-) :-)

Answer 12

Ruby, 87

p"Enter a dollar amount: "
n=gets.to_i;[20,10,5,1].map{|b|p"$#{b} bills = #{n/b}";n%=b}

Answer 13

C, 173

#include <stdio.h>
int n=20,c;int main(){
return (n-20||(printf("Enter a dollar amount: "),
scanf("%d",&c))),n?printf("$%d bills = %d\n",n,c/n),
c=c%n,(n/=2)-2||--n,main():0;}

All the linebreaks except the one after #include are removable. It's not the shortest solution, though it does make use of some less used features of C.

---

With some illegal hacks (C89 permits implicit int, C99 doesn't; C99 permits lack of return from main, C89 doesn't; neither permits omitting prototype of variadic printf) this still manages to compile and run in most compilers.

n=20,c;main(){n-20||(printf("Enter a dollar amount: "),scanf("%d",&c));
n?printf("$%d bills = %d\n",n,c/n),c=c%n,(n/=2)-2||--n,main():0;}

Only 136 characters (newlines removed)!

Answer 14

JavaScript, 135

JSBin Working Example

n=prompt('Enter a dollar amount: ');
s=[20,10,5,1];
for(i in s)
    b=s[i],
    document.write(b+' dollar bills = ' + Math.floor(n/b) + '<br/>'),
    n%=b;

Minified:

n=prompt('Enter a dollar amount: ');s=[20,10,5,1];for(i in s)b=s[i],document.write(b+' dollar bills = '+Math.floor(n/b)+'<br/>'),n%=b;

I can get it down to 129 characters if I cheat and remove semicolons, replace <br/> with \n, and leave an open <pre> at the end of the document:

n=prompt('Enter a dollar amount: ')s=[20,10,5,1]for(i in s)b=s[i],document.write(b+' dollar bills = '+Math.floor(n/b)+'\n'),n%=b

Answer 15

WinXP COM File

160 bytes

Source:

GetInput:
  mov si,offset Prompt
  call OutputString
  xor cx,cx
  xor bp,bp
  xor dx,dx
  mov bx,10
  mov di,Denoms
GetInputLoop:  
  mov ah,1
  int 21h
  mov ah,ch
  xchg ax,bp
  cmp bp,bx
  je DoneInput
  sub bp,'0'
  cmp bp,bx
  jae DoneInput
  mul bx
  add bp,ax
  adc dx,cx
  jmp GetInputLoop
EndDigits:  
  popa
  mov ax,dx
  xor dx,dx
  inc di
  cmp [di],cl
  je GetInput
DoneInput:
  pusha
  mov al,[di]
  aam
  add ax,'00'
  xchg ah,al
  mov word ptr [si+3],ax
  call OutputString
  popa  
  mov bl,[di]
  div bx
  pusha
  push cx
CalcDigitLoop:
  xor dx,dx
  mov bl,10
  div bx
  add dl,'0'
  push dx
  or ax,ax
  jnz CalcDigitLoop
PrintDigitLoop:
  pop dx
  or dx,dx
  jz EndDigits
  mov ah,2
  int 21h
  jmp PrintDigitLoop
OutputStringLoop:  
  mov ah,2
  mov dl,al
  int 21h
OutputString:
  lodsb
  or al,al
  jnz OutputStringLoop
  ret  
Prompt:
  db 10,13,'Enter a dollar amount: ',0
Output:
  db 10,13,'$   bills = ',0
Denoms:
  db 20,10,5,1,0

Skizz

Answer 16

JAVA, 245 chars

class G{
  public static void main(String[] a) throws Exception{
    System.out.println("Enter a dollar amount: ");
    int l = new java.util.Scanner(System.in).nextInt();
    for (int i : new int[] {20,10,5,1}) {System.out.println("$"+i+" bills = "+l/i);l%=i;}
  }
}

245 chars are achieved by removing all unnecessary whitespace. As shown above it weighs 283 chars.

Answer 17

GROOVY, 146 chars

println "Enter a dollar amount: "
l=System.in.newReader().readLine().toInteger()
[20,10,5,1].each{println "\$$it bills = ${(int)(l/it)}";l%=it;}

Not sure if there is any way to improve the readline part. It looks clumsy compared to other scripting languages. The (int) is unfortunately required because by default groovy deals with decimals not integers so we have to cast it down there.

Answer 18

Pascal, 204 chars

My first attempt at a code golf so I thought I'd keep it old-school. Compiled with the Free Pascal Compiler.

program a;uses sysutils;var i,b,c:integer;begin write('Enter a dollar amount: ');read(i);for b:=20 downto 1 do if b in[20,10,5,1]then begin c:=round(int(i/b));writeln('$',b,' bills = ',c);i-=b*c;end;end.

Answer 19

J

J has a built-in it calls "anti-base".

   0 2 2 5#:93
4 1 0 3
   0 2 2 5(#:,.~[:*/\.@}.[,1:)93
20 4
10 1
 5 0
 1 3

Unfortunately, the specified user interaction is impossible with only J built-ins.

Answer 20

Javascript, 105 characters

105 characters (using console)

for(s="",n=prompt("Enter a dollar amount: "),i=0;b=[20,10,5,1][i++];n%=b)s+="$"+b+" bills = "+~~(n/b)+"\n"\

114 characters

for(s="",n=prompt("Enter a dollar amount: "),i=0;b=[20,10,5,1][i++];n%=b)s+="$"+b+" bills = "+~~(n/b)+"\n";alert(s)

Formatted:

var b,
    s = "", // holds our result...
    n = prompt("Enter a dollar amount: "),
    i = 0,
    a = [20, 10, 5, 1];
// increment the array until we can't increment anymore.
// get the amount left after each iteration.
for(;b=a[i++]; n %= b){
                             /* "~~" == Math.floor() */
    s += "$" + b + " bills = " + ~~(n/b) + "\n";
}
// display the results...
alert(s);

Answer 21

Scala, 104

printf("Enter a dollar amount: ");(readInt/:Seq(20,10,5,1)){(a,b)=>printf("$%d bills = %d%n",b,a/b);a%b}

Answer 22

Too easy: DC - 73

A bit late, I know...

[Enter a dollar amount: ]P?20~A~5~1[36Pn[ bills = ]PnAP]dsPx5lPxAlPx20lPx

Answer 23

Vala, 223 Chars

The line breaks are not included and can be removed.

  public class BNC{public static int main(string[] p){
  int[] n={20,10,5,1};stdout.printf("Enter a dollar amount:");
  int a=stdin.read_line().to_int();foreach(int m in n){
  stdout.printf("$%i bills = % i\n",m,a/m);a%=m;}return 0;}}

---

Readable version:

  public class Main
  {
    public static int main (string[] args)
    {
        int[] notes = { 20, 10, 5, 1 };
        stdout.printf ("Enter a dollar amount:");
        int amount = stdin.read_line ().to_int ();

        foreach (int note in notes)
        {
            stdout.printf ("$%i bills = % i\n", note, amount / note);
            amount %= note;
        } 

      return 0;
    }
  }

Answer 24

Bash, 108 Chars

echo -n Enter a dollar amount:\ ;read t;for i in 20 10 5 1;do echo \$$i bills = $(($t/$i));t=$(($t%$i));done

Readable version:

echo -n Enter a dollar amount:\ 
read t
for i in 20 10 5 1
do
    echo \$$i bills = $(($t/$i))
    t=$(($t%$i))
done

Answer 25

OCaml, 138 chars

open Printf
let _=printf "Enter a dollar amount: ";List.fold_left
(fun a b->printf"$%d bills = %d\n"b(a/b);a mod b)(read_int())[20;10;5;1]

Answer 26

VBA

Was bored at work... 185 chars including all whitespaces

Sub a()
s = "Enter a dollar amount: "
i = InputBox(s)
Debug.Print s & i
For Each b In Array(20, 10, 5, 1)
c = Int(i / b)
i = i Mod b
Debug.Print "$" & b & " bills = " & c
Next
End Sub