sec1-4.htm

Fortran77和90/95编程入门,用于教学

mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>(6)CHARACTER</span><span
lang=ZH-CN style='mso-font-kerning:0pt'>语句</span><span lang=EN-US
style='mso-font-kerning:0pt'>(</span><span lang=ZH-CN style='mso-font-kerning:
0pt'>字符型说明语句</span><span lang=EN-US style='mso-font-kerning:0pt'>)<o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-59.4pt;
mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='color:fuchsia'>IMPLICIT</span><span
lang=ZH-CN style='color:fuchsia'>语句</span><span lang=EN-US style='color:fuchsia'>(</span><span
lang=ZH-CN style='color:fuchsia'>隐含说明语句</span><span lang=EN-US
style='color:fuchsia'>)</span><span lang=ZH-CN style='color:fuchsia'>指定</span><span
lang=ZH-CN>：可以用</span><span lang=EN-US>IMPLICIT</span><span lang=ZH-CN>语句将某一字母开头的全部变量指定为所需的类型，还可以用一个</span><span
lang=EN-US>IMPLICIT</span><span lang=ZH-CN>语句同时指定几种类型。例如：</span><span
lang=EN-US style='mso-font-kerning:0pt'><o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-.9pt;
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mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>IMPLICIT
INTEGER (A</span><span lang=ZH-CN style='mso-font-kerning:0pt'>，</span><span
lang=EN-US style='mso-font-kerning:0pt'>C</span><span lang=ZH-CN
style='mso-font-kerning:0pt'>，</span><span lang=EN-US style='mso-font-kerning:
0pt'>T-V)<o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-.9pt;
mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>IMPLICIT
REAL (I</span><span lang=ZH-CN style='mso-font-kerning:0pt'>，</span><span
lang=EN-US style='mso-font-kerning:0pt'>J)<o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-.9pt;
mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>IMPLICIT
INTEGER (A</span><span lang=ZH-CN style='mso-font-kerning:0pt'>，</span><span
lang=EN-US style='mso-font-kerning:0pt'>B)</span><span lang=ZH-CN
style='mso-font-kerning:0pt'>，</span><span lang=EN-US style='mso-font-kerning:
0pt'>REAL(I,K)</span><span lang=ZH-CN style='mso-font-kerning:0pt'>，</span><span
lang=EN-US style='mso-font-kerning:0pt'>INTEGER (X-Z)<o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-59.4pt;
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mso-char-indent-size:0cm'><span lang=ZH-CN>注：</span><span lang=EN-US>(1) </span><span
lang=ZH-CN>以上三种方法中，以类型说明语句最优先，</span><span lang=EN-US>IMPLICIT</span><span
lang=ZH-CN>语句次之，“</span><span lang=EN-US>I</span><span lang=ZH-CN>—</span><span
lang=EN-US>N</span><span lang=ZH-CN>规则”的隐含约定级别最低。如下程序中</span><span lang=EN-US>IMAX</span><span
lang=ZH-CN>变量为整型，而<span class=GramE>其它以</span></span><span lang=EN-US>I</span><span
lang=ZH-CN>、</span><span lang=EN-US>J</span><span lang=ZH-CN>开头的变量为实型：</span><span
lang=EN-US style='mso-font-kerning:0pt'><o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-.9pt;
mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>IMPLICIT
REAL(I</span><span lang=ZH-CN style='mso-font-kerning:0pt'>，</span><span
lang=EN-US style='mso-font-kerning:0pt'>J)<o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-.9pt;
mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>INTEGER
IMAX<o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-33.9pt;
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mso-char-indent-size:0cm'><span lang=EN-US>(2) </span><span lang=ZH-CN>类型说明语句和</span><span
lang=EN-US>IMPLICIT</span><span lang=ZH-CN>语句是非执行语句。</span><span lang=EN-US
style='mso-font-kerning:0pt'><o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-33.9pt;
mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>(3) </span><span
lang=ZH-CN style='mso-font-kerning:0pt'>类型说明只在本程序单位内有效。</span><span lang=EN-US
style='mso-font-kerning:0pt'><o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.4pt;text-indent:-33.9pt;
mso-char-indent-count:0;line-height:17.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>(4)
IMPLICIT</span><span lang=ZH-CN style='mso-font-kerning:0pt'>语句和类型说明语句应该出现在本程序单</span><span
lang=ZH-CN>位中的所有执行语句之前，其中</span><span lang=EN-US>IMPLICIT</span><span
lang=ZH-CN>语句又应在所有的类型说明语句之前。</span><span lang=EN-US style='mso-font-kerning:
0pt'><o:p></o:p></span></p>

<p class=MsoNormal align=center style='margin-top:15.6pt;margin-right:0cm;
margin-bottom:15.6pt;margin-left:0cm;mso-para-margin-top:1.0gd;mso-para-margin-right:
0cm;mso-para-margin-bottom:1.0gd;mso-para-margin-left:0cm;text-align:center;
line-height:200%;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt'><a
name="第1_4_2"><span lang=EN-US style='font-size:16.0pt;mso-bidi-font-size:12.0pt;
line-height:200%;mso-fareast-font-family:楷体_GB2312'>1.4.2</span></a><span
style='mso-bookmark:第1_4_2'></span><span lang=ZH-CN style='font-size:16.0pt;
mso-bidi-font-size:12.0pt;line-height:200%;font-family:楷体_GB2312;mso-ascii-font-family:
"Times New Roman";color:red'>内在函数</span><b><span lang=EN-US style='font-size:
16.0pt;mso-bidi-font-size:12.0pt;line-height:200%;mso-fareast-font-family:楷体_GB2312'><o:p></o:p></span></b></p>

<p class=MsoBodyTextIndent3 style='text-indent:24.0pt;mso-char-indent-count:
2.0;line-height:18.0pt;mso-line-height-rule:exactly;mso-char-indent-size:12pt'><span
lang=ZH-CN>用</span><span lang=EN-US>Fortran</span><span lang=ZH-CN>解题往往要用到一些专门运算。<span
class=GramE>如求三角函数</span></span><span lang=EN-US><span style='position:relative;
top:3.0pt;mso-text-raise:-3.0pt'><!--[if gte vml 1]><v:shapetype id="_x0000_t75"
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  <v:f eqn="if lineDrawn pixelLineWidth 0"/>
  <v:f eqn="sum @0 1 0"/>
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  <v:f eqn="sum @0 0 1"/>
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</v:shapetype><v:shape id="_x0000_i1025" type="#_x0000_t75" style='width:26.25pt;
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 <v:imagedata src="Sec1-4.files/image003.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=35 height=19
src="Sec1-4.files/image004.gif" v:shapes="_x0000_i1025"><![endif]></span><!--[if gte mso 9]><xml>
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</xml><![endif]--></span><span lang=ZH-CN>，</span><span lang=EN-US><span
style='position:relative;top:3.0pt;mso-text-raise:-3.0pt'><!--[if gte vml 1]><v:shape
 id="_x0000_i1026" type="#_x0000_t75" style='width:27pt;height:11.25pt' o:ole="">
 <v:imagedata src="Sec1-4.files/image005.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=36 height=15
src="Sec1-4.files/image006.gif" v:shapes="_x0000_i1026"><![endif]></span><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1026"
  DrawAspect="Content" ObjectID="_1068465322">
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</xml><![endif]--></span><span lang=ZH-CN>，<span class=GramE>开根</span></span><span
lang=EN-US><span style='position:relative;top:4.0pt;mso-text-raise:-4.0pt'><!--[if gte vml 1]><v:shape
 id="_x0000_i1027" type="#_x0000_t75" style='width:18.75pt;height:18pt' o:ole="">
 <v:imagedata src="Sec1-4.files/image007.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=25 height=24
src="Sec1-4.files/image008.gif" v:shapes="_x0000_i1027"><![endif]></span><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1027"
  DrawAspect="Content" ObjectID="_1068465323">
 </o:OLEObject>
</xml><![endif]--></span><span lang=ZH-CN>，绝对值</span><span lang=EN-US><span
style='position:relative;top:7.0pt;mso-text-raise:-7.0pt'><!--[if gte vml 1]><v:shape
 id="_x0000_i1028" type="#_x0000_t75" style='width:12.75pt;height:20.25pt'
 o:ole="">
 <v:imagedata src="Sec1-4.files/image009.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=17 height=27
src="Sec1-4.files/image010.gif" v:shapes="_x0000_i1028"><![endif]></span><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1028"
  DrawAspect="Content" ObjectID="_1068465324">
 </o:OLEObject>
</xml><![endif]--></span><span lang=ZH-CN>，对数</span><span lang=EN-US><span
style='position:relative;top:3.0pt;mso-text-raise:-3.0pt'><!--[if gte vml 1]><v:shape
 id="_x0000_i1029" type="#_x0000_t75" style='width:21pt;height:14.25pt' o:ole="">
 <v:imagedata src="Sec1-4.files/image011.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=28 height=19
src="Sec1-4.files/image012.gif" v:shapes="_x0000_i1029"><![endif]></span><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1029"
  DrawAspect="Content" ObjectID="_1068465325">
 </o:OLEObject>
</xml><![endif]--></span><span lang=ZH-CN>，指数</span><span lang=EN-US><span
style='position:relative;top:5.0pt;mso-text-raise:-5.0pt'><!--[if gte vml 1]><v:shape
 id="_x0000_i1030" type="#_x0000_t75" style='width:35.25pt;height:15.75pt'
 o:ole="">
 <v:imagedata src="Sec1-4.files/image013.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=47 height=21
src="Sec1-4.files/image014.gif" v:shapes="_x0000_i1030"><![endif]></span><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1030"
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 </o:OLEObject>
</xml><![endif]--></span><span lang=ZH-CN>，求一组数中最大数和<span class=GramE>最</span>小数等。</span><span
lang=EN-US>Fortran</span><span lang=ZH-CN>提供了一些系统<span style='color:fuchsia'>内在函数</span>来完成这些运算。程序设计者不必自己设计进行这些运算的语句组（即程序段或子程序），只需写出一个函数的名字以及结出一个或若干个自变量，就可以得到所需的值。例如：</span><span
lang=EN-US style='mso-font-kerning:0pt'><o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.5pt;text-indent:-34.0pt;
mso-char-indent-count:0;line-height:18.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US>SQRT(4.0)<span
style='mso-spacerun:yes'>&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
lang=ZH-CN>→ </span><span lang=EN-US><!--[if gte vml 1]><v:shape id="_x0000_i1031"
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 <v:imagedata src="Sec1-4.files/image015.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=25 height=23
src="Sec1-4.files/image016.gif" v:shapes="_x0000_i1031"><![endif]><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1031"
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 </o:OLEObject>
</xml><![endif]--></span><span lang=EN-US style='mso-font-kerning:0pt'><o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.5pt;text-indent:-34.0pt;
mso-char-indent-count:0;line-height:18.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>SIN(2.0)<span
style='mso-spacerun:yes'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
lang=ZH-CN style='mso-font-kerning:0pt'>→</span><span lang=EN-US
style='mso-font-kerning:0pt'> 2(</span><span lang=ZH-CN style='mso-font-kerning:
0pt'>弧度</span><span lang=EN-US style='mso-font-kerning:0pt'>)</span><span
lang=ZH-CN style='mso-font-kerning:0pt'>的正弦值</span><span lang=EN-US
style='mso-font-kerning:0pt'><span style='mso-spacerun:yes'>&nbsp; </span></span><span
lang=ZH-CN style='mso-font-kerning:0pt'>←</span><span lang=EN-US
style='mso-font-kerning:0pt'><span style='mso-spacerun:yes'>&nbsp; </span></span><span
lang=ZH-CN style='mso-font-kerning:0pt'>注意三角函数中的自变量单位为弧度！</span><span
lang=EN-US style='mso-font-kerning:0pt'><o:p></o:p></span></p>

<p class=MsoBodyTextIndent3 style='margin-left:59.5pt;text-indent:-34.0pt;
mso-char-indent-count:0;line-height:18.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>EXP(3.5)<span
style='mso-spacerun:yes'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
lang=ZH-CN style='mso-font-kerning:0pt'>→ </span><span lang=EN-US
style='mso-font-kerning:0pt'><!--[if gte vml 1]><v:shape id="_x0000_i1032"
 type="#_x0000_t75" style='width:18pt;height:15.75pt' o:ole="">
 <v:imagedata src="Sec1-4.files/image017.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=24 height=21
src="Sec1-4.files/image018.gif" v:shapes="_x0000_i1032"><![endif]><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1032"
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<p class=MsoBodyTextIndent3 style='margin-left:59.5pt;text-indent:-34.0pt;
mso-char-indent-count:0;line-height:18.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=EN-US style='mso-font-kerning:0pt'>LOG(3.0)<span
style='mso-spacerun:yes'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
lang=ZH-CN style='mso-font-kerning:0pt'>→ </span><span lang=EN-US
style='mso-font-kerning:0pt'><!--[if gte vml 1]><v:shape id="_x0000_i1033"
 type="#_x0000_t75" style='width:20.25pt;height:14.25pt' o:ole="">
 <v:imagedata src="Sec1-4.files/image019.wmz" o:title=""/>
</v:shape><![endif]--><![if !vml]><img border=0 width=27 height=19
src="Sec1-4.files/image020.gif" v:shapes="_x0000_i1033"><![endif]><!--[if gte mso 9]><xml>
 <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1033"
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<p class=MsoBodyTextIndent3 style='margin-left:59.5pt;text-indent:-34.0pt;
mso-char-indent-count:0;line-height:18.0pt;mso-line-height-rule:exactly;
mso-char-indent-size:0cm'><span lang=ZH-CN style='mso-font-kerning:0pt'>常用的</span><span
lang=EN-US style='mso-font-kerning:0pt'>Fortran77</span><span lang=ZH-CN
style='mso-font-kerning:0pt'>函数如下表所示。</span><span lang=EN-US style='mso-font-kerning:
0pt'><o:p></o:p></span></p>

<table class=MsoNormalTable border=1 cellspacing=0 cellpadding=0
 style='margin-left:27.95pt;border-collapse:collapse;mso-table-layout-alt:fixed;
 border:none;mso-border-alt:solid windowtext .75pt;mso-padding-alt:0cm 1.4pt 0cm 1.4pt'>
 <tr style='mso-yfti-irow:0'>
  <td width=66 valign=top style='width:49.65pt;border:solid windowtext 1.0pt;
  mso-border-alt:solid windowtext .75pt;padding:0cm 1.4pt 0cm 1.4pt'>
  <p class=MsoNormal align=center style='text-align:center'><span lang=ZH-CN
  style='font-size:12.0pt;font-family:宋体'>函数名</span><span lang=EN-US
  style='font-size:12.0pt;font-family:宋体'><o:p></o:p></span></p>
  </td>
  <td width=106 valign=top style='width:79.8pt;border:solid windowtext 1.0pt;
  border-left:none;mso-border-left-alt:solid windowtext .75pt;mso-border-alt:
  solid windowtext .75pt;padding:0cm 1.4pt 0cm 1.4pt'>
  <p class=MsoNormal align=cen