Complex$BAH$_9~$_(B

Ruby Development
41

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:34227] Re: Complexe$BAH$_9~$_e(B”
on Wed, 2 Apr 2008 21:21:33 +0900, Tadayoshi F. [email protected]
writes:

|> e$BM=8+$5$l$kLdBj$H$7$F$Oe(B
|>
|> * Smalltalke$B$de(BPythone$B$H0c$$!“e(BRubye$B$G$Oe(B//e$B$O6u$N@55,I=8=$H>WFMe(B
|> e$B$9$k!#e(B
|>
|> * /e$B$,$J$K$rJV$9$N$+e(B(e$B$^$@e(B)e$B$$$^$$$AL@3N$G$J$$!#8D?ME*$K$Oe(B
|> quoe$B$Oe(Brdive$B$HF1$8$G$”$k$HG’<1$7$F$$$^$9$,!“e(B/e$B$Oe(BFloate$B$G$”$ke(B
|> e$B$Y$-$J$N$+$J$"!#e(B
|
|e$B$=$&$G$7$g$&$M!#e(Bquo e$B$O!"e(B1.8 e$B$He(B 1.9 e$B$G>/$70c$$$^$9$,!“0UL#$H$7$F$Oe(B quo
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e$B$s$+!)e(B

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e$B$”$k$G$7$g$&$M!#e(B

e$B5$$K$J$k$N$Oe(B rational.quo(float) e$B$H$+$G!"e(B

(1) e$B@:EY$,Dc$$J}$K9g$o$;$ke(B
(2) e$B$h$j@53N$J%/%i%9$K9g$o$;$ke(B

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e$B$O<B:]$Ke(BRationale$B$de(BFloate$B$r;H$&?M$N0U8+$rJ9$-$?$$$b$N$G$9!#e(B

                            e$B$^$D$b$He(B e$B$f$-$R$me(B /:|)
42

e$BKNIt$G$9!#e(B

Shin-ichiro HARA e$B$5$s$O=q$-$^$7$?e(B:

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most
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e$BKNIt$5$s$NMQES$J$i%k!<%H$NCf$OJ?J}?t$G$"$k$3$H$,$o$+$C$F$$$k$N$G!"e(B
round e$B$G$$$$$G$9$,!#e(B

e$B7k6Ie(Bsqrte$B$N7k2L$H$7$F2?$,M_$7$$$+$OMQES$K$h$k$H;W$&$s$G$9$h$M!#@0?t$,M_$7e(B
e$B$$>l9g$G$be(Bnearest
integere$B$,$[$7$$$H$+e(Bfloore$B$,$[$7$$$H$+$"$k$/$i$$$J$o$1$G!#e(B

43

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:34229] Re: Complexe$BAH$_9~$_e(B”
on Wed, 2 Apr 2008 23:27:36 +0900, Tadayoshi F. [email protected]
writes:

|e$B@53N$H$$$&$N$,$I$&$$$&$b$N$+$o$+$j$^$;$s$,!“4pK\E*$K$O!”$=$l$G$$$$$H;We(B
|e$B$$$^$9!#e(Brational e$B$rJV$9$,$$$$$H;W$$$^$9$,!"$=$l$O$^$?JL$N2]Bj$@$H9M$(e(B
|e$B$F$$$$$H;W$$$^$9!#e(B

e$B$5$C$-%3%%C%H$7$?%3!<%I$G$Oe(Brdiv,
quoe$B$Oe(BRationale$B$rJV$9$h$&$Ke(B
e$B$7$F$$^$7$?!#$3$l$GLdBj$,5/$-$J$$$+$I$&$+3NG’$9$kI,MW$,$"$je(B
e$B$^$9$M!#e(B

|10e$BG/6a$/A0$N5DO@$G$b>/$7OC$,$"$j$^$7$?$,!"e(BFloat e$B$OJL$b$N$G!"e(BFloat e$B$r$De(B
|e$B$+$&$H!“1x@w$5$l$k!”$H$$$&$3$H$K$J$C$F$$$^$9$M!#e(BCommon Lisp e$B$G$O!"e(B
|floating-point contagion e$B$H$$$&$h$&$G$9$,!#e(B

e$B$=$&$_$?$$$G$9$M!#:#2s!"e(Bfloate$B$r4^$`3d$j;;$Oe(B

  • /e$B$G$Oe(Bfloat
  • rdiv, quoe$B$G$Oe(B(e$B$`$j$d$je(B)rational

e$B$H$$$&Iw$K$7$F$_$^$7$?!#e(Brdive$B$,e(Bfloate$B$rJV$9$N$O$*$+$7$$$7!"e(Bquo
e$B$O$?$V$se(Brdive$B$Ne(Baliase$B$@$m$&$H9M$($?$+$i$G$9!#e(B

44

e$BB<ED$G$9!%e(B

2008/4/2 Yukihiro M. [email protected]:

e$B$7$F$$$k$N$G!“e(B(2)e$B$NJ}$,NI$$$h$&$K;W$C$F$$$^$9!#$7$+$7!”$=$NJUe(B
e$B$O<B:]$Ke(BRationale$B$de(BFloate$B$r;H$&?M$N0U8+$rJ9$-$?$$$b$N$G$9!#e(B

e$B$U$J$P$5$s$,e(B [ruby-dev:34229]
e$B$G6D$C$F$$$k$h$&$K!$IbF0>.?tE@?t$Oe(B
e$BB>$N@53N$J?t$r?)$C$F$7$^$&$H9M$($?J}$,NI$$$G$9!%0lC6IbF0>.?tE@?t$Ke(B
e$BJQ49$7$F7W;;$7$?CM$r@53N$K@0?t$dM-M}?t$KJQ49$G$-$k$3$H$O4|BT$G$-e(B
e$B$J$$$O$:$G$9!%$b$7$I$&$7$F$bJQ49$9$kI,MW$,$“$k$J$i!$$=$N$h$&$Je(B
e$BLdBj$,$”$k$3$H$rM}2r$7$?$&$($Ge(B Float#to_r
e$B$GL@<(E*$K9T$o$l$k$Y$-e(B
e$B$G$7$g$&!%$G$9$+$i!$FbIt$Ge(B Float e$B$re(B Rational
e$B$KJQ49$7$F$+$i2?$+$r9T$&e(B
e$B%a%=%C%I$d1i;;$OB8:_$7$J$$J}$,?F@Z$G$O$J$$$+$H;W$$$^$9!%e(B

45

(a) rdive$B$Ke(Bfloate$B$,:.$8$C$?$i%(%i!<e(B
(b) floate$B$r$`$j$d$je(Brationale$B$KJQ49$7$Fe(B(e$B$3$l$O2DG=e(B)e$B7W;;B39Te(B
© floate$B$,:.$8$C$?$ie(Brdive$B$@$m$&$,e(Bfloate$B$rJV$9e(B
(d) e$B$=$NB>e(B

e$B$3$N7o$K8B$i$:!"4pK\E*$Ke(B ruby e$B$G$Oe(B ©
e$B$J$s$@$H;W$$$^$9!#e(B

quo e$B$O!“0cOB46$,$”$j$^$9$M!#7k2L$H$7$F!"@53N$Ke(B Rational
e$B$GI=8==PMh$k$Je(B
e$B$i0UL#$,$"$j$^$9$,!"e(BRational
e$B$K$9$l$P@53N$H$$$&$o$1$G$O$J$$$N$G!#e(B

rdiv
e$B$O!"$=$&$$$&$b$N$@$H8@$o$l$l$P!"$=$&$$$&$b$N$J$N$+$J$H$$$&5$$,$7e(B
e$B$J$$$G$b$"$j$^$;$s!#$,!“L5M}$K86B’$KH?$9$k$3$H$r$9$kI,MW$,$”$k$+$N$O5?e(B
e$BLd$G$9!#e(B

46

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:34232] Re: Complexe$BAH$_9~$_e(B”
on Thu, 3 Apr 2008 04:26:17 +0900, “Kenta M.”
[email protected] writes:

|e$B$U$J$P$5$s$,e(B [ruby-dev:34229] e$B$G6D$C$F$$$k$h$&$K!$IbF0>.?tE@?t$Oe(B
|e$BB>$N@53N$J?t$r?)$C$F$7$^$&$H9M$($?J}$,NI$$$G$9!%0lC6IbF0>.?tE@?t$Ke(B
|e$BJQ49$7$F7W;;$7$?CM$r@53N$K@0?t$dM-M}?t$KJQ49$G$-$k$3$H$O4|BT$G$-e(B
|e$B$J$$$O$:$G$9!%e(B

e$B$=$l$OL5M}$G$7$g$&$M!#8m:9$N$3$H$^$G9M$($k$HFC$K!#e(B

|e$B$b$7$I$&$7$F$bJQ49$9$kI,MW$,$“$k$J$i!$$=$N$h$&$Je(B
|e$BLdBj$,$”$k$3$H$rM}2r$7$?$&$($Ge(B Float#to_r e$B$GL@<(E*$K9T$o$l$k$Y$-e(B
|e$B$G$7$g$&!%$G$9$+$i!$FbIt$Ge(B Float e$B$re(B Rational e$B$KJQ49$7$F$+$i2?$+$r9T$&e(B
|e$B%a%=%C%I$d1i;;$OB8:_$7$J$$J}$,?F@Z$G$O$J$$$+$H;W$$$^$9!%e(B

e$B$U$`!“$=$N>l9g!“e(Brdiv(e$B$D$^$j7k2L$,e(Brationale$B$G$”$k$3$H$,4|BT$5e(B
e$B$l$ke(Bdiv)e$B$,e(Bfloate$B$rM?$($i$l$?>l9g!”$I$N$h$&$JF0:n$r$9$Y$-$G$7$ge(B
e$B$&$+!#$^$“!”$I$&$G$b$h$$$C$A$c$=$NDL$j$J$s$G$9$,!"<BAu$9$k?He(B
e$B$H$7$F$O$J$s$H$+5sF0$rDj5A$7$J$$$H$$$1$J$$$s$G!#e(B

(a) rdive$B$Ke(Bfloate$B$,:.$8$C$?$i%(%i!<e(B
(b)
floate$B$r$`$j$d$je(Brationale$B$KJQ49$7$Fe(B(e$B$3$l$O2DG=e(B)e$B7W;;B39Te(B
(c) floate$B$,:.$8$C$?$ie(Brdive$B$@$m$&$,e(Bfloate$B$rJV$9e(B
(d) e$B$=$NB>e(B

e$B8=:_$Oe(B(b)e$B$N5sF0$K$J$C$F$^$9!#e(B

                            e$B$^$D$b$He(B e$B$f$-$R$me(B /:|)
47

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:34235] Re: Complexe$BAH$_9~$_e(B”
on Thu, 3 Apr 2008 21:35:04 +0900, Tadayoshi F. [email protected]
writes:

|> (a) rdive$B$Ke(Bfloate$B$,:.$8$C$?$i%(%i!<e(B
|> (b) floate$B$r$`$j$d$je(Brationale$B$KJQ49$7$Fe(B(e$B$3$l$O2DG=e(B)e$B7W;;B39Te(B
|> (c) floate$B$,:.$8$C$?$ie(Brdive$B$@$m$&$,e(Bfloate$B$rJV$9e(B
|> (d) e$B$=$NB>e(B
|
|e$B$3$N7o$K8B$i$:!"4pK\E*$Ke(B ruby e$B$G$Oe(B (c) e$B$J$s$@$H;W$$$^$9!#e(B

e$B$=$&$J$s$G$9$+$M!#$?$@!“$=$&$9$k$He(BRationale$B$rJV$5$J$$$3$H$,$“e(B
e$B$k0J>ee(Brdive$B$H$$$&L>A0$K$O13$,$”$k$o$1$G$9$+$i!“F3F~$7$F$O$$$1e(B
e$B$J$$$b$N$G$”$k$H$$$&$3$H$Ke(B(e$B;d$N463P$G$Oe(B)e$B$J$j$^$9!#e(B(c)e$B$G$”$k$He(B
e$B7h$a$k$J$ie(B(e$B$=$l$K$OH?BP$7$^$;$se(B)e$B!"e(BNumeric#rdive$B$b<h$j=|$/$Y$-e(B
e$B$G$7$g$&!#e(B

|quo e$B$O!“0cOB46$,$”$j$^$9$M!#7k2L$H$7$F!“@53N$Ke(B Rational e$B$GI=8==PMh$k$Je(B
|e$B$i0UL#$,$”$j$^$9$,!"e(BRational e$B$K$9$l$P@53N$H$$$&$o$1$G$O$J$$$N$G!#e(B

e$B$=$3$K$OF10U$7$^$9!#e(B

|rdiv e$B$O!“$=$&$$$&$b$N$@$H8@$o$l$l$P!”$=$&$$$&$b$N$J$N$+$J$H$$$&5$$,$7e(B
|e$B$J$$$G$b$"$j$^$;$s!#$,!“L5M}$K86B’$KH?$9$k$3$H$r$9$kI,MW$,$”$k$+$N$O5?e(B
|e$BLd$G$9!#e(B

e$B$=$l$,K\Ev$K!V86B’!W$J$N$+;d$K$O$h$/$o$+$j$^$;$s$,!“L>$,BN$re(B
e$B8=$5$J$$$3$H$NJ}$,!”;d$K$H$C$F$O86B’$KH?$9$k$3$H$G$9!#7+$jJVe(B
e$B$7$K$J$j$^$9$,!“e(B(c)e$B$,!V86B’!W$G$”$k$N$G$"$l$Pe(Brdive$B$H$$$&L>A0$Oe(B
e$B$J$/$7$F!"2DG=$J;~$K$Oe(BRationale$B$rJV$9e(B(Floate$B$,:.$8$l$Pe(BFloat)e$B$Ne(B
e$B3d$j;;$H$7$F$Ne(Bquoe$B$rDs6!$7$^$7$g$&!#e(B

                            e$B$^$D$b$He(B e$B$f$-$R$me(B /:|)
48

|e$B$3$N7o$K8B$i$:!"4pK\E*$Ke(B ruby e$B$G$Oe(B © e$B$J$s$@$H;W$$$^$9!#e(B

e$B$=$&$J$s$G$9$+$M!#$?$@!"$=$&$9$k$He(BRationale$B$rJV$5$J$$$3$H$,$“e(B
e$B$k0J>ee(Brdive$B$H$$$&L>A0$K$O13$,$”$k$o$1$G$9$+$i!“F3F~$7$F$O$$$1e(B
e$B$J$$$b$N$G$”$k$H$$$&$3$H$Ke(B(e$B;d$N463P$G$Oe(B)e$B$J$j$^$9!#e(B©e$B$G$"$k$He(B
e$B7h$a$k$J$ie(B(e$B$=$l$K$OH?BP$7$^$;$se(B)e$B!"e(BNumeric#rdive$B$b<h$j=|$/$Y$-e(B
e$B$G$7$g$&!#e(B

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e$B$j$^$9$M!#e(B

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|e$B$J$$$G$b$"$j$^$;$s!#$,!“L5M}$K86B’$KH?$9$k$3$H$r$9$kI,MW$,$”$k$+$N$O5?e(B
|e$BLd$G$9!#e(B

e$B$=$l$,K\Ev$K!V86B’!W$J$N$+;d$K$O$h$/$o$+$j$^$;$s$,!“L>$,BN$re(B
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e$B$J$/$7$F!"2DG=$J;~$K$Oe(BRationale$B$rJV$9e(B(Floate$B$,:.$8$l$Pe(BFloat)e$B$Ne(B
e$B3d$j;;$H$7$F$Ne(Bquoe$B$rDs6!$7$^$7$g$&!#e(B

e$B:#$N$3$H$m!"$=$l$G$b$$$$$h$&$J5$$,$7$^$9!#e(B

49

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:34240] Re: Complexe$BAH$_9~$_e(B”
on Thu, 3 Apr 2008 22:11:39 +0900, Tadayoshi F. [email protected]
writes:

|> e$B$=$&$J$s$G$9$+$M!#$?$@!“$=$&$9$k$He(BRationale$B$rJV$5$J$$$3$H$,$“e(B
|> e$B$k0J>ee(Brdive$B$H$$$&L>A0$K$O13$,$”$k$o$1$G$9$+$i!“F3F~$7$F$O$$$1e(B
|> e$B$J$$$b$N$G$”$k$H$$$&$3$H$Ke(B(e$B;d$N463P$G$Oe(B)e$B$J$j$^$9!#e(B(c)e$B$G$”$k$He(B
|> e$B7h$a$k$J$ie(B(e$B$=$l$K$OH?BP$7$^$;$se(B)e$B!"e(BNumeric#rdive$B$b<h$j=|$/$Y$-e(B
|> e$B$G$7$g$&!#e(B
|
|e$B7k6IL>A0$K$R$C$Q$i$l$F$k$@$1$G!"2?$r$7$?$$$N$+$O$h$/$o$+$i$$$H$3$m$,$"e(B
|e$B$j$^$9$M!#e(B

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e$B$$$J$$e(B(rdive$B$OBP>N@-$+$iF3F~$5$l$?$b$N$@$HM}2r$7$F$$$^$9e(B)e$B$N$G!“e(B
e$BL>A0$,<BBV$H0[$J$k$N$G$”$l$P!“:o$C$F$7$^$C$?J}$,$h$$$H;W$$$^e(B
e$B$9!#$G$O!”$=$NJ}8~$G:n6H$7$F$_$^$9!#e(B