碼表上的順序來決定，此順序亦為字符的值。strcmp()首先將s1第一個(gè)字符值減去s2第一個(gè)字符值，若差值為0則再繼續(xù)比較下個(gè)字符，若差值不為0則將差值返回。例如字符串"Ac"和"ba"比較則會(huì)返回字符"A"(65)和'b'(98)的差值(－33)。<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(shù)s1和s2字符串相同則返回0。s1若大于s2則返回大于0的值。s1若小于s2則返回小于0 
      的值。<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;string.h&gt;<br>
      main()<br>
      {<br>
      char *a="aBcDeF";<br>
      char *b="AbCdEf";<br>
      char *c="aacdef";<br>
      char *d="aBcDeF";<br>
      printf("strcmp(a,b) : %d\n",strcmp(a,b));<br>
      printf("strcmp(a,c) : %d\n",strcmp(a,c));<br>
      printf("strcmp(a,d) : %d\n",strcmp(a,d));<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執(zhí)行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> strcmp(a,b) : 32<br>
      strcmp(a,c) :-31<br>
      strcmp(a,d) : 0<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc56></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>
      strcoll（采用目前區(qū)域的字符排列次序來比較字符串） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> strcmp，bcmp，memcmp，strcasecmp，strncasecmp<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;string.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(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> int strcoll( const char *s1, const 
      char *s2);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> strcoll()會(huì)依環(huán)境變量LC_COLLATE所指定的文字排列次序來比較s1和s2 
      字符串。<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(shù)s1和s2字符串相同則返回0。s1若大于s2則返回大于0的值。s1若小于s2則返回小于0 
      的值。<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'> 若LC_COLLATE為"POSIX"或"C"，則strcoll()與strcmp()作用完全相同。<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'> 參考strcmp()。<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc57></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>
      strcpy（拷貝字符串） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> bcopy，memcpy，memccpy，memmove<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;string.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(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> char *strcpy(char *dest,const 
      char *src);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> strcpy()會(huì)將參數(shù)src字符串拷貝至參數(shù)dest所指的地址。<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'> 返回參數(shù)dest的字符串起始地址。<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'> 如果參數(shù)dest所指的內(nèi)存空間不夠大，可能會(huì)造成緩沖溢出(buffer 
      Overflow)的錯(cuò)誤情況，在編寫程序時(shí)請(qǐng)?zhí)貏e留意，或者用strncpy()來取代。<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;string.h&gt;<br>
      main()<br>
      {<br>
      char a[30]="string(1)";<br>
      char b[]="string(2)";<br>
      printf("before strcpy() :%s\n",a);<br>
      printf("after strcpy() :%s\n",strcpy(a,b));<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執(zhí)行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> before strcpy() :string(1)<br>
      after strcpy() :string(2)<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc58></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>
      strcspn（返回字符串中連續(xù)不含指定字符串內(nèi)容的字符數(shù)） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> strspn<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'> #inclued&lt;string.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(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> size_t strcspn ( const char *s,const 
      char * reject);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> strcspn()從參數(shù)s字符串的開頭計(jì)算連續(xù)的字符，而這些字符都完全不在參數(shù)reject 
      所指的字符串中。簡單地說，若strcspn()返回的數(shù)值為n，則代表字符串s開頭連續(xù)有n個(gè)字符都不含字符串reject內(nèi)的字符。<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'> 返回字符串s開頭連續(xù)不含字符串reject內(nèi)的字符數(shù)目。<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;string.h&gt;<br>
      main()<br>
      {<br>
      char *str="Linux was first developed for 386/486-based pcs.";<br>
      printf("%d\n",strcspn(str," "));<br>
      printf("%d\n",strcspn(str,"/-"));<br>
      printf("%d\n",strcspn(str,"1234567890"));<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執(zhí)行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> 5 /*只計(jì)算到“ ”的出現(xiàn)，所以返回“Linux”的長度*/<br>
      33 /*計(jì)算到出現(xiàn)“/”或“－”，所以返回到“6”的長度*/<br>
      30 /* 計(jì)算到出現(xiàn)數(shù)字字符為止，所以返回“3”出現(xiàn)前的長度*/<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc59></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>
      strdup（復(fù)制字符串） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> calloc，malloc，realloc，free<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;string.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(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> char * strdup( const char *s);<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 函數(shù)說明 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> strdup()會(huì)先用maolloc()配置與參數(shù)s字符串相同的空間大小，然后將參數(shù)s字符串的內(nèi)容復(fù)制到該內(nèi)存地址，然后把該地址返回。該地址最后可以利用free()來釋放。<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'> 返回一字符串指針，該指針指向復(fù)制后的新字符串地址。若返回NULL表示內(nèi)存不足。<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;string.h&gt;<br>
      main()<br>
      {<br>
      char a[]="strdup";<br>
      char *b;<br>
      b=strdup(a);<br>
      printf("b[ ]=\"%s\"\n",b);<br>
      }<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 執(zhí)行 </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> b[ ]="strdup"<br>
      </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top">　 
      <div align="right"><br>
        <font face='宋體' size='2'><a name=linuxc60></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>
      strlen（返回字符串長度） </font> </td>
  </tr>
  <tr> 
    <td width="80" valign="top"> 
      <div align="right"><font face='宋體' size='2'> 相關(guān)函數(shù) </font> </div>
    </td>
    <td valign="top"> <font face='宋體' size='2'> <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;string.h&gt;<br>
      </font> </td>