Code Golf: Numeric equivalent of an Excel column name

Answer 1

APL

13 characters

Put the value in x:

x←'WTF'

then compute it with:

26⊥(⎕aV⍳x)-65

The only reason J beat me is because of the parentheses. I'm thinking there should be some way to rearrange it to avoid the need for them, but it's been a long day. Ideas?

(Heh, you perl programmers with your 30+ character solutions are so cute!)

Answer 2

C:

int r=0;
while(*c)r=r*26+*c++-64;

String is stored in 'c', value is in 'r'.

Answer 3

C89, 58 characters

s;main(c){while(c=getchar()+1)s=26*s+c-65;printf("%d",s);}

The input (stdin) must contain only A-Z, no other characters (including newlines) are allowed.

Answer 4

Brainf*ck, 81 characters (no whitespace)

,[>>>[->>+++++[-<+++++>]<+<]>[-<+>]<<++++++++[<++++++++>-]<[<->-]<[>>>+<<<-],]>>>

Explanation

,[  // get character input into p[0], enter loop if it isn't null (0)
>>>[->>+++++[-<+++++>]<+<] // take what's in p[3] and multiply by 26, storing it in p[4]
>[-<+>] // copy p[4] back to p[3]
<<++++++++[<++++++++>-]< // store 64 in p[1]
[<->-]< // subtract p[1], which is 64, from the input char to get it's alphabetical index
[>>>+<<<-] // add p[0] to p[3]
,] // get another character and repeat
>>> // move to p[3], where our final result is stored

So you'll notice I didn't actually convert the numerical value to an ascii string for printing. That would likely ruin the fun. But I did the favor of moving the pointer to the cell with the result, so at least it's useful to the machine.

Hey, what do you know, I beat C#!

Answer 5

Ruby 1.9, 21 characters

p'A'.upto(gets).count

Tests:

$ echo -n A| ruby x.rb
1
$ echo -n WTF| ruby x.rb
16074
$ echo -n ROFL| ruby x.rb
326676

Answer 6

Java: 112 124 characters

class C{public static void main(String[]a){int r=0;for(int b:a[0].getBytes())r=26*r+b-64;System.out.print(r);}}