Long multiplication: Difference between revisions

=={{header|APL}}==

{{works with|Dyalog APL}}

This function takes two digit vectors of arbitrary size.

<syntaxhighlight lang="apl">longmul←{⎕IO←0

sz←⌈/≢¨x y←↓⌽↑⌽¨⍺⍵

ds←+⌿↑(⌽⍳sz)⌽¨↓(¯2×sz)↑[1]x∘.×y

mlt←{(1⌽⌊⍵÷10)+10|⍵}⍣≡⊢ds

0=≢mlt←(∨\0≠mlt)/mlt:,0

mlt

}</syntaxhighlight>

{{out}}

<syntaxhighlight lang="apl"> ⎕←input←longmul⍣63⍨⊢,2 ⍝ construct 2*64

1 8 4 4 6 7 4 4 0 7 3 7 0 9 5 5 1 6 1 6

⎕←longmul⍨input ⍝ calculate 2*128

3 4 0 2 8 2 3 6 6 9 2 0 9 3 8 4 6 3 4 6 3 3 7 4 6 0 7 4 3 1 7 6 8 2 1 1 4 5 6</syntaxhighlight>