Print the alphabet Christmas tree

Question

I know it's 1.5 weeks after Christmas but trying to print an isosceles triangle in a monospaced font makes it look weird.

Challenge

Print the alphabet from A to Z so that it forms a filled triangle in the output. For each line in the output, starting from "A", add the next letter.

No inputs, only outputs. Pad the leading edge of the triangle with spaces.

Best answer is the code with the least bytes.

Output

            A
            AB
           ABC
           ABCD
          ABCDE
          ABCDEF
         ABCDEFG
         ABCDEFGH
        ABCDEFGHI
        ABCDEFGHIJ
       ABCDEFGHIJK
       ABCDEFGHIJKL
      ABCDEFGHIJKLM
      ABCDEFGHIJKLMN
     ABCDEFGHIJKLMNO
     ABCDEFGHIJKLMNOP
    ABCDEFGHIJKLMNOPQ
    ABCDEFGHIJKLMNOPQR
   ABCDEFGHIJKLMNOPQRS
   ABCDEFGHIJKLMNOPQRST
  ABCDEFGHIJKLMNOPQRSTU
  ABCDEFGHIJKLMNOPQRSTUV
 ABCDEFGHIJKLMNOPQRSTUVW
 ABCDEFGHIJKLMNOPQRSTUVWX
ABCDEFGHIJKLMNOPQRSTUVWXY
ABCDEFGHIJKLMNOPQRSTUVWXYZ

Sample Java Code (430 bytes)

public static void main(String args[]) {
    String spaces = "";
    String alpha = "";
    char A = 'A';

    for (int i = 0; i < 26; i++) {
        for (int j = 13 - (i/2); j > 0; j--) {
           spaces += " ";
        }

        alpha += (char)(A + i);

        System.out.println(spaces + alpha);
        spaces = "";
    } 
}

Answer 1

Ruby, 44 bytes

t=''
26.times{|x|puts' '*(12-x/2)+(t<<65+x)}

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Answer 2

05AB1E, 5 bytes

Auη.c

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Exlpanation

A        # push the alphabet
 u       # convert to upper case
  η      # get list of prefixes
   .c    # centralize, focused to the left

Answer 3

SOGL V0.12, 8 bytes

'⁸∫Zm}¹╚

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Explanation:

'⁸        push 26
  ∫  }    that many times, pushing the counter
   Zm       mold the alphabet to the counters length
      ¹   wrap the stack in an array
       ╚  center horizontally

Answer 4

C# (.NET Core), 114 + 18 = 132 bytes

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()=>string.Join("\n",new int[26].Select((i,e)=>"ABCDEFGHIJKLMNOPQRSTUVWXYZ".Substring(0,e+1).PadLeft(13+(e+1)/2)))

Answer 5

J, ₃₈ 36 bytes

echo(' '<@#"0~2#i._13),&><\u:65+i.26

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This is honestly disgusting.

39 bytes

echo(2#i._13)(>@],~' '#~[)"0<\u:65+i.26

Explanation

These will be snippets of the code built up from a REPL session. Three spaces means an input, and no spaces means the output from it.

The alphabet

First we generate the alphabet by making the range [65,90] and converting this to unicode using u:.

   65 + i.10 NB. truncated
65 66 67 68 69 70 71 72 73 74
   u: 65 + i.26
ABCDEFGHIJKLMNOPQRSTUVWXYZ

Then we generate the A, AB, etc. sections by taking all of the prefixes of the alphabet and boxing them using <\

   <\ u: 65 + i.5 NB. truncated again
┌─┬──┬───┬────┬─────┐
│A│AB│ABC│ABCD│ABCDE│
└─┴──┴───┴────┴─────┘

The padding

We need to pad the alphabet with 12, 12, 11, 11, etc. spaces. So first we construct this range using i. with a negative argument (which makes it go from that value minus 1 to 0, descending).

   i. _13
12 11 10 9 8 7 6 5 4 3 2 1 0

We then copy each value twice

   2 # i. _13
12 12 11 11 10 10 9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 0 0

And then copy the space character as many times as specified, boxing it because J would pad the matrix with spaces to fill otherwise.

   '*' #"0~ 2 # i. _5 NB. truncated, and using '*' so you can see the output
****
****
*** 
*** 
**  
**  
*   
*   
    NB. This line is empty
    NB. This line is empty, too

Getting the output

Then we just join the two together using , (unboxing first using &>) and write to STDOUT using echo. There's nothing to show here since it's just the output.

Answer 6

Excel (VBA), 129 82 bytes

Using Immediate Window.  and cell [A1] as output.

For x=25to 0Step -1:For y=x to 25:b=b &Chr(65+y-x):Next:?Space(x/2.01)&b:b="":Next

Answer 7

Perl 5, 32 bytes

say$"x(13-++$k/2),A..$_ for A..Z

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Answer 8

C,  84  81 bytes

Thanks to @ceilingcat for saving three bytes!

f(i,j){for(i=1;i++<27;puts(""))for(j=51;j<63-~i/2;)putchar(j++<64-i/2?32:j+i/2);}

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Unrolled:

f(i, j) // Using the argument list only to declare the variables.
{
    for (i=1; i++<27; puts(""))
        for (j=51; j<63-~i/2;)
            putchar(j++<64-i/2 ? 32 : j+i/2);
}

Answer 9

Jelly, 12 bytes

ØAJ’HU⁶ẋż¹ƤY

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Uses code very similar to the linked question (further evidence that it is most likely a dupe).

-3 bytes thanks to FlipTack and Jonathan Allan (though indirectly)

Old version, 15 bytes

12Rx2U⁶ẋżØA¹Ƥ¤Y

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