📄 csdn_文档中心_cstring,string,char的综合比较(一).htm
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</SPAN></SPAN></SPAN><FONT size=3><SPAN
lang=EN-US>string</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是最方便的，几乎可以直接用所有的字符串赋值，包括</SPAN><SPAN
lang=EN-US>CString</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">和</SPAN><SPAN
lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><FONT size=3><SPAN
lang=EN-US>CString</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">次之，可以直接用些基本的字符串赋值，包括</SPAN><SPAN
lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等；</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><FONT size=3><SPAN lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">只能由指针赋值，并且是极危险的操作，建议使用</SPAN><SPAN
lang=EN-US>strcpy</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">或者</SPAN><SPAN
lang=EN-US>memcpy</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，而且</SPAN><SPAN
lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在声明的时候如未赋初值建议先设为</SPAN><SPAN
lang=EN-US>NULL</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，以避免野指针，令你抓狂；</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><FONT
size=3>举例：</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>char *psz = NULL;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><FONT
size=3><SPAN lang=EN-US>psz = new char[10]; //</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">当然，以上的直接写成</SPAN><SPAN
lang=EN-US>char *psz = new char[10];</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">也是一样</SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>memset( psz, 0, 10 );</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>strcpy( psz, “joise” ); </FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>CString cstr;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>cstr = psz;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>string str;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>str = psz;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>str = cstr;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 42pt"><SPAN
lang=EN-US><FONT size=3>delete []psz;</FONT></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 18pt; TEXT-INDENT: 0cm; mso-list: l1 level5 lfo1; tab-stops: list 18.0pt"><SPAN
lang=EN-US style="mso-fareast-font-family: 'Times New Roman'"><SPAN
style="mso-list: Ignore"><FONT size=3>b)</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><SPAN lang=EN-US><FONT
size=3>operator+</FONT></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><FONT size=3><SPAN
lang=EN-US>string</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与</SPAN><SPAN
lang=EN-US>CString</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">差不多，可以直接与</SPAN><SPAN
lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">进行加法，但不可以相互使用</SPAN><SPAN
lang=EN-US>+</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">运算符，即</SPAN><SPAN
lang=EN-US>string str = str + cstr</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是非法的，须转换成</SPAN><SPAN
lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><FONT size=3><SPAN lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">没有</SPAN><SPAN
lang=EN-US>+</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">运算，只能使用</SPAN><SPAN
lang=EN-US>strcat</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">把两个指针连在一起；</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><FONT
size=3>举例：</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><SPAN
lang=EN-US><FONT size=3>char* psz = “joise”;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><SPAN
lang=EN-US><FONT size=3>CString cstr = psz;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><SPAN
lang=EN-US><FONT size=3>cstr = cstr + psz;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><SPAN
lang=EN-US><FONT size=3>string str = psz;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><SPAN
lang=EN-US><FONT size=3>str = str + str + psz;</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><SPAN
lang=EN-US><FONT size=3>strcat( psz, psz );</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><FONT
size=3><SPAN lang=EN-US>strcat( psz, cstr );//</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">合法</SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt 36pt"><FONT
size=3><SPAN lang=EN-US>strcat( psz, str );//</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">非法，由此可见，</SPAN><SPAN
lang=EN-US>CString</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">可自动转换为</SPAN><SPAN
lang=EN-US>const char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，而</SPAN><SPAN
lang=EN-US>string</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">不行</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 36pt; TEXT-INDENT: -18pt; mso-list: l1 level5 lfo1; tab-stops: list 36.0pt"><SPAN
lang=EN-US style="mso-fareast-font-family: 'Times New Roman'"><SPAN
style="mso-list: Ignore"><FONT size=3>c)</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><SPAN lang=EN-US><FONT size=3>operator
+=</FONT></SPAN></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><FONT size=3><SPAN
lang=EN-US>string</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是最强大的，几乎可以与所有的字符串变量</SPAN><SPAN
lang=EN-US>+=</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，包括</SPAN><SPAN
lang=EN-US>CString</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">和</SPAN><SPAN
lang=EN-US>char*</SPAN><SPAN
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 0cm 0cm 0pt 42pt; TEXT-INDENT: -21pt; mso-list: l0 level1 lfo2; tab-stops: list 42.0pt left 63.0pt"><SPAN
lang=EN-US
style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><SPAN
style="mso-list: Ignore"><FONT size=3>²</FONT><SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN><FONT size=3><SPAN
lang=EN-US>CString</SPAN><SPAN
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