c++常见问题答案.htm

面试题 希望对大家有所帮助 成功走向程序员之路

                  style="COLOR: blue; FONT-FAMILY: 宋体">（</SPAN><SPAN lang=EN-US 
                  style="COLOR: blue">2</SPAN></STRONG><STRONG><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">分）</SPAN><SPAN lang=EN-US 
                  style="COLOR: blue"><O:P></O:P></SPAN></STRONG></P>
                  <P class=MsoNormal><STRONG><SPAN lang=EN-US 
                  style="COLOR: blue"><SPAN>&nbsp;&nbsp;&nbsp; 
                  </SPAN><SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</SPAN><O:P></O:P></SPAN></STRONG></P>
                  <P class=MsoNormal style="TEXT-INDENT: 52.5pt"><STRONG><SPAN 
                  lang=EN-US style="COLOR: blue">sizeof ( n ) 
                  =<SPAN>&nbsp;&nbsp; </SPAN>4<SPAN>&nbsp;&nbsp; 
                  </SPAN></SPAN></STRONG><STRONG><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">（</SPAN><SPAN lang=EN-US 
                  style="COLOR: blue">2</SPAN></STRONG><STRONG><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">分）</SPAN></STRONG><SPAN 
                  lang=EN-US style="COLOR: blue"><O:P></O:P></SPAN></P></TD>
                <TD 
                style="BORDER-RIGHT: windowtext 1pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 213.05pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid; HEIGHT: 61.55pt" 
                vAlign=top width=284>
                  <P class=MsoNormal><SPAN lang=EN-US style="COLOR: blue">void 
                  Func ( char str[100])<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="COLOR: blue">{<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">请计算</SPAN><SPAN 
                  lang=EN-US style="COLOR: blue"><O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 21pt"><SPAN lang=EN-US 
                  style="COLOR: blue"><SPAN>&nbsp;</SPAN><STRONG>sizeof( str ) 
                  =<SPAN>&nbsp;&nbsp; </SPAN>4 
                  <SPAN>&nbsp;&nbsp;&nbsp;&nbsp;</SPAN></STRONG></SPAN><STRONG><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">（</SPAN><SPAN lang=EN-US 
                  style="COLOR: blue">2</SPAN></STRONG><STRONG><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">分）</SPAN><SPAN lang=EN-US 
                  style="COLOR: blue"><O:P></O:P></SPAN></STRONG></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="COLOR: blue">}<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="COLOR: blue"><O:P>&nbsp;</O:P></SPAN></P></TD></TR>
              <TR style="HEIGHT: 61.55pt; page-break-inside: avoid">
                <TD 
                style="BORDER-RIGHT: 1pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 213.05pt; PADDING-TOP: 0cm; BORDER-BOTTOM: 1pt solid; HEIGHT: 61.55pt" 
                vAlign=top width=284>
                  <P class=MsoNormal><SPAN lang=EN-US style="COLOR: blue">void 
                  *p = malloc( 100 );<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">请计算</SPAN><SPAN 
                  lang=EN-US style="COLOR: blue"><O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 31.6pt"><STRONG><SPAN 
                  lang=EN-US style="COLOR: blue">sizeof ( p ) =<SPAN>&nbsp; 
                  </SPAN>4<SPAN>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
                  </SPAN></SPAN></STRONG><STRONG><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">（</SPAN><SPAN lang=EN-US 
                  style="COLOR: blue">2</SPAN></STRONG><STRONG><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">分）</SPAN><SPAN lang=EN-US 
                  style="COLOR: blue"><O:P></O:P></SPAN></STRONG></P>
                  <P class=MsoNormal style="TEXT-INDENT: 41.9pt"><SPAN 
                  lang=EN-US 
              style="COLOR: blue"><O:P>&nbsp;</O:P></SPAN></P></TD></TR>
              <TR style="HEIGHT: 61.55pt; page-break-inside: avoid">
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体">for (i=0; i&lt;N; 
                i++)<O:P></O:P></SPAN> 
                <P></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体">{<O:P></O:P></SPAN></P>
                <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体">if 
                (condition)<O:P></O:P></SPAN></P>
                <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体"><SPAN>&nbsp;&nbsp;&nbsp; 
                </SPAN>DoSomething();<O:P></O:P></SPAN></P>
                <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体">else<O:P></O:P></SPAN></P>
                <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体"><SPAN>&nbsp;&nbsp;&nbsp; 
                </SPAN>DoOtherthing();<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体">}</SPAN> </P>
                <TD 
                style="BORDER-RIGHT: 1pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 213.05pt; PADDING-TOP: 0cm; BORDER-BOTTOM: 1pt solid; HEIGHT: 61.55pt" 
                vAlign=top width=284><SPAN lang=EN-US style="COLOR: blue">if 
                  (condition)<O:P></O:P></SPAN></TD>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue">{<O:P></O:P></SPAN> 
                <P></P>
                <P class=MsoNormal><SPAN lang=EN-US style="COLOR: blue">for 
                (i=0; i&lt;N; i++)<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue"><SPAN>&nbsp;&nbsp;&nbsp; 
                </SPAN>DoSomething();<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue">}<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue">else<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue">{<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue"><SPAN>&nbsp;&nbsp;&nbsp; </SPAN>for (i=0; 
                i&lt;N; i++)<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue"><SPAN>&nbsp;&nbsp;&nbsp; 
                </SPAN>DoOtherthing();<O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue">}<O:P></O:P></SPAN></P>
                <P></P>
                <P></P></P></TR>
              <TR style="HEIGHT: 61.55pt; page-break-inside: avoid">
                <P class=MsoNormal><STRONG><SPAN 
                style="COLOR: blue; FONT-FAMILY: 宋体">优点：程序简洁<SPAN 
                lang=EN-US><O:P></O:P></SPAN></SPAN></STRONG> 
                <P></P>
                <P class=MsoNormal><STRONG><SPAN lang=EN-US 
                style="COLOR: blue; FONT-FAMILY: 宋体"><O:P>&nbsp;</O:P></SPAN></STRONG></P>
                <P class=MsoNormal><STRONG><SPAN 
                style="COLOR: blue; FONT-FAMILY: 宋体">缺点：多执行了<SPAN 
                lang=EN-US>N-1</SPAN>次逻辑判断，并且打断了循环“流水线”作业，使得编译器不能对循环进行优化处理，降低了效率。</SPAN></STRONG> 
                </P>
                <TD 
                style="BORDER-RIGHT: 1pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 213.05pt; PADDING-TOP: 0cm; BORDER-BOTTOM: 1pt solid; HEIGHT: 61.55pt" 
                vAlign=top width=284><SPAN 
                  style="COLOR: blue; FONT-FAMILY: 宋体">优点：循环的效率高</SPAN><SPAN 
                  lang=EN-US style="COLOR: blue"><O:P></O:P></SPAN></TD>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue"><O:P>&nbsp;</O:P></SPAN> 
                <P></P>
                <P class=MsoNormal><SPAN 
                style="COLOR: blue; FONT-FAMILY: 宋体">缺点：程序不简洁</SPAN><SPAN 
                lang=EN-US style="COLOR: blue"><O:P></O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue"><O:P>&nbsp;</O:P></SPAN></P>
                <P class=MsoNormal><SPAN lang=EN-US 
                style="COLOR: blue"><O:P>&nbsp;</O:P></SPAN></P>
                <P></P>
                <P></P></P></TR></TBODY></TABLE>
            <P class=MsoNormal><SPAN lang=EN-US 
            style="COLOR: blue"><O:P>&nbsp;</O:P></SPAN></P>
            <P class=MsoNormal><SPAN lang=EN-US><O:P>&nbsp;</O:P></SPAN></P>
            <P class=MsoNormal><SPAN lang=EN-US><O:P>&nbsp;</O:P></SPAN></P>
            <P class=MsoNormal><SPAN 
            style="FONT-FAMILY: 宋体">、请简述以下两个</SPAN><SPAN 
            lang=EN-US>for</SPAN><SPAN style="FONT-FAMILY: 宋体">循环的优缺点</SPAN></P>
            <P class=MsoNormal><SPAN lang=EN-US 
            style="FONT-FAMILY: 宋体"><O:P>&nbsp;</O:P></SPAN></P>
            <TABLE class=MsoNormalTable 
            style="BORDER-RIGHT: medium none; BORDER-TOP: medium none; MARGIN-LEFT: 11pt; BORDER-LEFT: medium none; BORDER-BOTTOM: medium none; BORDER-COLLAPSE: collapse" 
            cellSpacing=0 cellPadding=0 border=1>
              <TBODY>
              <TR style="HEIGHT: 59.6pt">
                <TD 
                style="BORDER-RIGHT: windowtext 1pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 1pt solid; WIDTH: 201.35pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid; HEIGHT: 59.6pt" 
                vAlign=top width=268>
                  <P class=MsoNormal><SPAN lang=EN-US style="FONT-FAMILY: 宋体">// 
                  </SPAN><SPAN style="FONT-FAMILY: 宋体">第一个<SPAN 
                  lang=EN-US><O:P></O:P></SPAN></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="FONT-FAMILY: 宋体">for (i=0; i&lt;N; 
                  i++)<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="FONT-FAMILY: 宋体">{<O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN 
                  lang=EN-US style="FONT-FAMILY: 宋体">if 
                  (condition)<O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN 
                  lang=EN-US style="FONT-FAMILY: 宋体"><SPAN>&nbsp;&nbsp;&nbsp; 
                  </SPAN>DoSomething();<O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN 
                  lang=EN-US style="FONT-FAMILY: 宋体">else<O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN 
                  lang=EN-US style="FONT-FAMILY: 宋体"><SPAN>&nbsp;&nbsp;&nbsp; 
                  </SPAN>DoOtherthing();<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="FONT-FAMILY: 宋体">}<O:P></O:P></SPAN></P></TD>
                <TD 
                style="BORDER-RIGHT: windowtext 1pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 1pt solid; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 212.4pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid; HEIGHT: 59.6pt" 
                vAlign=top width=283>
                  <P class=MsoNormal><SPAN lang=EN-US style="FONT-FAMILY: 宋体">// 
                  </SPAN><SPAN style="FONT-FAMILY: 宋体">第二个<SPAN 
                  lang=EN-US><O:P></O:P></SPAN></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US style="FONT-FAMILY: 宋体">if 
                  (condition)<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="FONT-FAMILY: 宋体">{<O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 21.8pt"><SPAN 
                  lang=EN-US style="FONT-FAMILY: 宋体">for (i=0; i&lt;N; 
                  i++)<O:P></O:P></SPAN></P>
                  <P class=MsoNormal style="TEXT-INDENT: 10.9pt"><SPAN 
                  lang=EN-US style="FONT-FAMILY: 宋体"><SPAN>&nbsp;&nbsp;&nbsp; 
                  </SPAN>DoSomething();<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="FONT-FAMILY: 宋体">}<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US 
                  style="FONT-FAMILY: 宋体">else<O:P></O:P></SPAN></P>
                  <P class=MsoNormal><SPAN lang=EN-US