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Magic Square Demo
REBOL [
Title: "Magic Square program"
Author: "Gregg Irwin"
Comment: {
Credit to Bob Kurosaka and Martin Gardener for inspiration.
}
]
get-size: has [result] [
print "Enter the size of the square's side."
print ""
result: to-integer ask "It must be an odd number larger than 1 : "
if any [(result < 3) (even? result)] [get-size]
result
]
edge-guard: does [
if row < 1 [row: row + side]
if col > side [col: col - side]
if row > side [row: row - side]
if col < 1 [col: col + side]
]
print-square: func [square side] [
print ["Magic Square, Order " side]
print ["Each row, col, and Diagonal add up to " side * (side ** 2 + 1) / 2]
print ""
repeat row side [
repeat col side [
prin [pick square/:row col tab]
]
print ""
]
print ""
]
magic-square: func [/size sz [integer!]] [
side: either size [sz][get-size]
row: 1
col: (side + 1) / 2 ;Locate the starting cell
square: array/initial reduce [side side] 0
poke square/:row col 1 ;Initialize the first value
for i 2 to-integer (side ** 2) 1 [
row: row - 1
col: col + 1 ;Northeast move
edge-guard
if 0 <> pick square/:row col [
row: row + 1 ;otherwise retreat
col: col - 1
row: row + 1 ;Break move
edge-guard
]
poke square/:row col i
]
print-square square side
]
;-- 0 based version --
; print-square: func [square side] [
; print ["Magic Square, Order " side]
; print ["Each row, col, and Diagonal add up to " side * (side ** 2 + 1) / 2 - side]
; print ""
; repeat row side [
; repeat col side [
; prin [pick square/:row col tab]
; ]
; print ""
; ]
; print ""
; ]
;
; magic-square: func [/size sz [integer!]] [
; side: either size [sz][get-size]
; row: 1
; col: (side + 1) / 2 ;Locate the starting cell
; square: array/initial reduce [side side] none
; poke square/:row col 0 ;Initialize the first value
;
; repeat i to-integer (side ** 2) - 1 [
; row: row - 1
; col: col + 1 ;Northeast move
; edge-guard
; if none <> pick square/:row col [
; row: row + 1 ;otherwise retreat
; col: col - 1
; row: row + 1 ;Break move
; edge-guard
; ]
; poke square/:row col i
; ]
; print-square square side
; ]
;-- End 0 based version --
magic-square
;magic-square/size 5
halt
