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<TD align=right><A href="http://www.csdn.net/">CSDN</A> - <A
href="http://www.csdn.net/develop/">文檔中心</A> - <FONT
color=#003399>其他開發語言 </FONT> </TD></TR>
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<TD align=middle bgColor=#003399 height=10><FONT
color=#ffffff>標題</FONT></TD>
<TD><B> 新的C語言：一切都源于FORTRAN</B> MatrixCpp（翻譯）
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<TD align=middle bgColor=#003399><FONT color=#ffffff>關鍵字</FONT></TD>
<TD width=500> C，受限指針</TD></TR>
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<TD align=middle bgColor=#003399 height=10><FONT
color=#ffffff>出處</FONT></TD>
<TD height=10> <A
href="http://www.cuj.com%20%20and%20《dr.dobb/" 軟件研發》?
s>http://www.cuj.com%20%20and%20《dr.dobb/</A></TD></TR>
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<P class=MsoPlainText style="TEXT-INDENT: 18pt"><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 宋體; mso-bidi-font-family: 宋體">此篇文章摘取于即將登載于《</SPAN><SPAN
lang=EN-US style="COLOR: white; FONT-SIZE: 9pt"><A
href="http://www.china-pub.com/computers/common/info.asp?id=13341"><SPAN
style="FONT-SIZE: 10.5pt">Dr.Dobb's 軟件研發</SPAN></A></SPAN><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 宋體; mso-bidi-font-family: 宋體">》第三期（<SPAN
lang=EN-US>2003年10月）的《The New
C:一切源于FORTRAN》，文章主要是介紹了C99的新特性受限指針，在得到作者Randy
Meyers以及《</SPAN></SPAN><SPAN lang=EN-US
style="COLOR: white; FONT-SIZE: 9pt"><A
href="http://www.china-pub.com/computers/common/info.asp?id=13341"><SPAN
style="FONT-SIZE: 10.5pt">Dr.Dobb's 軟件研發</SPAN></A></SPAN><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 宋體; mso-bidi-font-family: 宋體">》雜志負責人劉江先生的應允下，把全文的前面的一部分作為文檔發表，希望能對大家有所幫助。</SPAN></P>
<P class=MsoPlainText style="TEXT-INDENT: 18pt"><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 宋體; mso-bidi-font-family: 宋體"></SPAN> </P>
<P class=MsoPlainText style="TEXT-INDENT: 18pt"><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 宋體; mso-bidi-font-family: 宋體"> </P>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><SPAN
style="FONT-FAMILY: 宋體; FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">新的</SPAN></B><B><SPAN
lang=EN-US
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">C</SPAN></B><B><SPAN
style="FONT-FAMILY: 宋體; FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">語言：一切都源于</SPAN></B><B><SPAN
lang=EN-US
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">FORTRAN</SPAN></B></P>
<P class=MsoPlainText
style="TEXT-INDENT: 18pt; mso-char-indent-count: 2.0; mso-char-indent-size: 9.0pt"><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 宋體; mso-bidi-font-family: 宋體">譯注：本文是作者<SPAN
lang=EN-US>Randy Meyers在 CUJ雜志開的一個專題系列The New
C的第二篇文章，主要是敘說C99中的新關鍵字restrict以及</SPAN></SPAN><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt">受限指針（<SPAN
lang=EN-US>restricted
pointers）的歷史淵源和使用方式。受限指針作為一種編譯器優化代碼的方式，是由編譯器廠商提供特定的實現，因此這篇文章所談論的并非在一切實現中都能得到支持，至于如何使用restrict關鍵字，這篇文章做了很好的說明，</SPAN></SPAN><SPAN
style="FONT-SIZE: 9pt; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 宋體; mso-bidi-font-family: 宋體">期望本文能給關心<SPAN
lang=EN-US>C語言和使用C語言的用戶帶來幫助。在翻譯上，所有譯者在翻譯過程中有疑惑的術語或者其他一切都以括號形式把原文直接給出，誠心不想給讀者半點誤導，但是否如愿還需讀者的評判，<A
href="mailto:關于本文的一切可以用amstrongest@hotmail.com">關于本文的一切可以用amstrongest@hotmail.com</A>與譯者聯系和討論。<?xml:namespace
prefix = o ns = "urn:schemas-microsoft-com:office:office"
/><o:p></o:p></SPAN></SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US> <o:p></o:p></SPAN></P>
<P class=MsoNormal
style="TEXT-INDENT: 52.5pt; mso-char-indent-count: 5.0; mso-char-indent-size: 10.5pt"><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">有時候改進一種語言的最好方式就是讓它和三十年前的古老樣子更相似</SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
lang=EN-US> <o:p></o:p></SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
lang=EN-US> <o:p></o:p></SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
lang=EN-US> <o:p></o:p></SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">一切都源于</SPAN><SPAN
lang=EN-US>FORTRAN</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">（</SPAN><SPAN
lang=EN-US>It all began with FORTRAN</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">）。</SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
lang=EN-US> <o:p></o:p></SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">談起上面的話，我并不是想說</SPAN><SPAN
lang=EN-US>FORTRAN</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">是第一個程序設計語言，但是在上個世紀六十年代（</SPAN><SPAN
lang=EN-US>1960s</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">）的一場關于如何在</SPAN><SPAN
lang=EN-US>FORTRAN</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">中實現參數傳遞的爭論，卻意外的使</SPAN><SPAN
lang=EN-US>FORTRAN</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">在七十年代（</SPAN><SPAN
lang=EN-US>1970s</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">）的超級計算機上面的性能有了巨大的提升，并且導致了九十年代（</SPAN><SPAN
lang=EN-US>1990s</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">）一個關于</SPAN><SPAN
lang=EN-US>C</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">語言的新特征被</SPAN><SPAN
lang=EN-US>C99</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">所接受，這就是受限指針（</SPAN><SPAN
lang=EN-US>restricted pointers</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">）。而理解受限指針的原始動機的最好方式就是回顧歷史，重溫發生在</SPAN><SPAN
lang=EN-US>FORTRAN</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">中的那個由爭論所導致的意外。</SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
lang=EN-US> <o:p></o:p></SPAN></P>
<P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">和</SPAN><SPAN
lang=EN-US>C</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">不一樣的是，在</SPAN><SPAN
lang=EN-US>FORTRAN</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">中如果一個函數被分配了一個新值作為參數，傳遞給函數的實參值將會改變，并且在函數返回時，調用者將會得到新的參數值。考慮下面</SPAN><SPAN
lang=EN-US>Example 1</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">所例舉的代碼，如果你以</SPAN><SPAN
lang=EN-US>Y</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">作為參數調用</SPAN><SPAN
lang=EN-US>F</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">，在</SPAN><SPAN
lang=EN-US>F</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">返回時，</SPAN><SPAN
lang=EN-US>Y</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">值將會是</SPAN><SPAN
lang=EN-US>6</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">。</SPAN><SPAN
lang=EN-US>[</SPAN><SPAN
style="FONT-FAMILY: 宋體; mso-hansi-font-family: 'Times New Roman'; mso-ascii-font-family: 'Times New Roman'">譯注：下面的程序沒有出現變量</SPAN><SPAN
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