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Narcissistic decimal number: Difference between revisions
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=={{header|REXX}}==
This is an idiomatic approach.
===version 1===
<lang rexx>/*REXX program to generate and display a number of narcissistic numbers.*/
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do j=1 until #==N; L=length(j) /*get the length of the J number.*/
s=left(j,1)**L /*1st digit in J raised to L pow.*/
/* [↑] calculate partial sum. */▼
do k=2 for L-1 /*perform for each digit in J. */
s=s+substr(j,k,1)**L /*add digit raised to pow to sum.*/
if s>j then iterate j /*perform a short-circuit test. */
end /*k*/ /* [↑] calculate the rest of sum*/
/* [↓] perform final "sum" test.*/▼
if s\==j then iterate /*does sum equal to J? No ∙∙∙ */
#=#+1 /*bump the narcissistic num count*/
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25 narcissistic: 24678050
</pre>
===version 2===
This REXX version is optimized to pre-compute all the ten (single) digits raised to all possible powers (which is 39).
<lang rexx>/*REXX program to generate and display a number of narcissistic numbers.*/
numeric digits 39 /*be able to handle the largest #*/
parse arg N .; if N=='' then N=25 /*get number of narcissistic #'s.*/
N=min(N,89) /*there are 89 narcissistic #s.*/
do w=1 for 39 /*generate tables: digits ^ L pow*/
do i=0 for 10; @.w.i=i**w; end /*build table of 10 digs ^ L pow.*/
end /*w*/ /* [↑] table is of a fixed size.*/
#=0 /*number of narcissistic # so far*/
do j=1 until #==N; L=length(j) /*get the length of the J number.*/
s=0 /*sum of the J digs ^ L (so far)*/
do k=1 for L /*perform for each digit in J. */
_=substr(j,k,1) /*select a single digit to sum. */
s=s+@.L._ /*add digit raised to pow to sum.*/
if s>j then iterate j /*perform a short-circuit test. */
if s\==j then iterate /*does sum equal to J? No ∙∙∙ */
#=#+1 /*bump the narcissistic num count*/
say right(#,9) ' narcissistic:' j /*display index & narcissistic #.*/
end /*j*/ /* [↑] this list starts at 1. */
'''output''' is the same as REXX version 1.
<br>
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