<div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      isdigit（測試字符是否為阿拉伯數字） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> isxdigit<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;ctype.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> int isdigit(int c)<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 檢查參數c是否為阿拉伯數字0到9。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 若參數c為阿拉伯數字，則返回TRUE，否則返回NULL(0)。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 附加說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 此為宏定義，非真正函數。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 范例 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> /* 找出str字符串中為阿拉伯數字的字符*/<br>
      #include&lt;ctype.h&gt;<br>
      main()<br>
      {<br>
      char str[]="123@#FDsP[e?";<br>
      int i;<br>
      for(i=0;str[i]!=0;i++)<br>
      if(isdigit(str[i])) printf("%c is an digit character\n",str[i]);<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 1 is an digit character<br>
      2 is an digit character<br>
      3 is an digit character<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc6></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      isgraphis（測試字符是否為可打印字符） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> isprint<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include &lt;ctype.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> int isgraph (int c)<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 檢查參數c是否為可打印字符，若c所對映的ASCII碼可打印，且非空格字符則返回TRUE。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 若參數c為可打印字符，則返回TRUE，否則返回NULL(0)。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 附加說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 此為宏定義，非真正函數。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 范例 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> /* 判斷str字符串中哪些為可打印字符*/<br>
      #include&lt;ctype.h&gt;<br>
      main()<br>
      {<br>
      char str[]="a5 @;";<br>
      int i;<br>
      for(i=0;str[i]!=0;i++)<br>
      if(isgraph(str[i])) printf("str[%d] is printable character:%d\n",i,str[i]);<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> str[0] is printable character:a<br>
      str[1] is printable character:5<br>
      str[3] is printable character:@<br>
      str[4] is printable character:;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc7></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      islower（測試字符是否為小寫字母） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> isalpha，isupper<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;ctype.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> int islower(int c)<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 檢查參數c是否為小寫英文字母。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 若參數c為小寫英文字母，則返回TRUE，否則返回NULL(0)。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 附加說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 此為宏定義，非真正函數。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 范例 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;ctype.h&gt;<br>
      main()<br>
      {<br>
      char str[]="123@#FDsP[e?";<br>
      int i;<br>
      for(i=0;str[i]!=0;i++)<br>
      if(islower(str[i])) printf("%c is a lower-case character\n",str[i]);<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> c is a lower-case character<br>
      s is a lower-case character<br>
      e is a lower-case character<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc8></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <br>
      isprint（測試字符是（否為可打印字符） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> isgraph<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 表頭文件 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> #include&lt;ctype.h&gt;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 定義函數 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> int isprint(int c);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 檢查參數c是否為可打印字符，若c所對映的ASCII碼可打印，其中包含空格字符，則返回TRUE。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 返回值 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 若參數c為可打印字符，則返回TRUE，否則返回NULL(0)。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 附加說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 此為宏定義，非真正函數。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 范例 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> /* 判斷str字符串中哪些為可打印字符包含空格字符*/<br>
      #include&lt;ctype.h&gt;<br>
      main()<br>
      {<br>
      char str[]="a5 @;";<br>
      int i;<br>
      for(i=0;str[i]!=0;i++)<br>
      if(isprint(str[i])) printf("str[%d] is printable character:%d\n",i,str[i]);<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> str[0] is printable character:a<br>
      str[1] is printable character:5<br>
      str[2] is printable character:<br>
      str[3] is printable character:@<br>
      str[4] is printable character:;<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc9></a></font> </div>
    </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> <br>
        </font> </div>