Multiplication tables
Produce a formatted 12×12 multiplication table of the kind memorised by rote when in primary school.
You are encouraged to solve this task according to the task description, using any language you may know.
Only print the top half triangle of products.
ALGOL 68
<lang Algol68>main:(
INT max = 12; STRING empty cell = " "; FORMAT fmt = $zz-d$;
print(" x");
FOR col TO max DO printf((fmt, col)) OD;
print (new line);
FOR row TO max DO printf((fmt,row)); FOR col TO row-1 DO print(empty cell) OD; [row:max]INT product; FOR col FROM row TO max DO product[col]:=row*col OD; printf((fmt, product, $l$)) OD
)</lang> Output:
x 1 2 3 4 5 6 7 8 9 10 11 12 1 1 2 3 4 5 6 7 8 9 10 11 12 2 4 6 8 10 12 14 16 18 20 22 24 3 9 12 15 18 21 24 27 30 33 36 4 16 20 24 28 32 36 40 44 48 5 25 30 35 40 45 50 55 60 6 36 42 48 54 60 66 72 7 49 56 63 70 77 84 8 64 72 80 88 96 9 81 90 99 108 10 100 110 120 11 121 132 12 144
Haskell
<lang haskell>import Text.Printf
main = do
putStrLn $ " x" ++ concatMap fmt [1..12]
mapM_ putStrLn $ zipWith f [1..12] $ iterate (" " ++) ""
where f n s = fmt n ++ s ++ concatMap (fmt . (*n)) [n..12]
fmt n = printf "%4d" (n :: Int)</lang>
Tcl
<lang tcl>puts " x\u2502 1 2 3 4 5 6 7 8 9 10 11 12" puts \u0020\u2500\u2500\u253c[string repeat \u2500 48] for {set i 1} {$i <= 12} {incr i} {
puts -nonewline [format "%3d" $i]\u2502[string repeat " " [expr {$i*4-4}]]
for {set j 1} {$j <= 12} {incr j} {
if {$j >= $i} { puts -nonewline [format "%4d" [expr {$i*$j}]] }
} puts ""
}</lang> Output:
x│ 1 2 3 4 5 6 7 8 9 10 11 12 ──┼──────────────────────────────────────────────── 1│ 1 2 3 4 5 6 7 8 9 10 11 12 2│ 4 6 8 10 12 14 16 18 20 22 24 3│ 9 12 15 18 21 24 27 30 33 36 4│ 16 20 24 28 32 36 40 44 48 5│ 25 30 35 40 45 50 55 60 6│ 36 42 48 54 60 66 72 7│ 49 56 63 70 77 84 8│ 64 72 80 88 96 9│ 81 90 99 108 10│ 100 110 120 11│ 121 132 12│ 144