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Pascal's triangle: Difference between revisions
→{{header|Common Lisp}}: Added another solution using pretty-printing
(Added Algol W) |
(→{{header|Common Lisp}}: Added another solution using pretty-printing) |
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:repeat n
:collect a))</lang>
Another iterative solution, this time using pretty-printing to automatically print the triangle in the shape of a triangle in the terminal. The pascal-print function determines the length of the final row and uses it to decide how wide the triangle should be.
<lang lisp>
(defun next-pascal (l)
`(1 ,@(loop for i from 0 to (- (length l) 2)
collect (+ (nth i l) (nth (1+ i) l)))
1))
(defun pascal-print (r)
(let* ((pasc (loop with p = (list (list 1))
repeat r do (nconc p (list (apply #'next-pascal (last p))))
finally (return p)))
(len (length (format nil "~A" (car (last pasc))))))
(format t (format nil "~~{~~~D:@<~~{~~A ~~}~~>~~%~~}" len) pasc)))
</lang>
For example:
<lang lisp>(pascal-print 4)</lang>
<lang>
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
</lang>
<lang lisp>(pascal-print 8)</lang>
<lang>
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1
1 6 15 20 15 6 1
1 7 21 35 35 21 7 1
1 8 28 56 70 56 28 8 1
</lang>
=={{header|D}}==
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