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39 lines
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<TITLE>CLHS: Section 2.4.8.11</TITLE>
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<H1><A REV=MADE HREF="http://www.lispworks.com/"><IMG WIDTH=80 HEIGHT=65 ALT="[LISPWORKS]" SRC="../Graphics/LWSmall.gif" ALIGN=Bottom></A><A REL=TOP HREF="../Front/index.htm"><IMG WIDTH=237 HEIGHT=65 ALT="[Common Lisp HyperSpec (TM)]" SRC="../Graphics/CLHS_Sm.gif" ALIGN=Bottom></A> <A REL=PREV HREF="02_dhj.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="02_dh.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="02_dhl.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<H2>
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2.4.8.11 Sharpsign C</H2> <P>
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<TT>#C</TT> reads a following <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>object</I></A>, which must be a <A REL=DEFINITION HREF="26_glo_l.htm#list"><I>list</I></A> of length two whose <A REL=DEFINITION HREF="26_glo_e.htm#element"><I>elements</I></A> are both <I>reals</I>. These <I>reals</I> denote, respectively, the real and imaginary parts of a <A REL=DEFINITION HREF="26_glo_c.htm#complex"><I>complex</I></A> number. If the two parts as notated are not of the same data type, then they are converted according to the rules of floating-point <A REL=DEFINITION HREF="26_glo_c.htm#contagion"><I>contagion</I></A> described in <A REL=CHILD HREF="12_aab.htm">Section 12.1.1.2 (Contagion in Numeric Operations)</A>. <P>
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<TT>#C(</TT><I>real</I><TT> </TT><I>imag</I><TT>)</TT> is equivalent to <TT>#.(complex (quote </TT><I>real</I><TT>) (quote </TT><I>imag</I><TT>))</TT>, except that <TT>#C</TT> is not affected by <A REL=DEFINITION HREF="v_rd_eva.htm#STread-evalST"><B>*read-eval*</B></A>. See the <A REL=DEFINITION HREF="26_glo_f.htm#function"><I>function</I></A> <A REL=DEFINITION HREF="f_comp_2.htm#complex"><B>complex</B></A>. <P>
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The next figure contains examples of the use of <TT>#C</TT>. <P>
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<PRE>
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#C(3.0s1 2.0s-1) ;A <A REL=DEFINITION HREF="26_glo_c.htm#complex">complex</A> with small float parts.
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#C(5 -3) ;A ``Gaussian integer''
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#C(5/3 7.0) ;Will be converted internally to #C(1.66666 7.0)
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#C(0 1) ;The imaginary unit; that is, i.
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</PRE>
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<P><B>Figure 2-21. Complex Number Example</B> <P>
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For further information, see <A REL=CHILD HREF="22_acad.htm">Section 22.1.3.1.4 (Printing Complexes)</A> and <A REL=CHILD HREF="02_cbc.htm">Section 2.3.2.3 (Syntax of a Complex)</A>. <P>
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<P><HR>The following <A REL=META HREF="../Front/X3J13Iss.htm">X3J13 cleanup issue</A>, <I>not part of the specification</I>, applies to this section:<P><UL><LI> <A REL=CHILD HREF="../Issues/iss288.htm">READ-SUPPRESS-CONFUSING:GENERALIZE</A><P></UL><HR>
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