subject_50721.htm

vc

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序号：50721 发表者：Fe 发表日期：2003-08-26 08:44:48
<br>主题：菜鸟提问：-&gt; 符号是什么意思啊
<br>内容：比如 pStatic3-&gt;SetWindowText("")<BR>刚刚开始学vc，c＋＋也只大概看了一遍。<BR>请指导
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回复者：michael 回复日期：2003-08-26 08:50:57
<br>内容：Structure, Union, and Class Member Operators:&nbsp;&nbsp;.&nbsp;&nbsp;and -&gt;<BR>postfix-expression<BR><BR>. identifier <BR><BR>postfix-expression<BR><BR>–&gt; identifier<BR><BR>A “member-selection expression” refers to members of structures, unions, and classes. Such an expression has the value and type of the selected member. <BR><BR>This list describes the two forms of the member-selection expressions: <BR><BR>In the first form, postfix-expression represents a value of struct, class, or union type, and identifier names a member of the specified structure, union, or class. The value of the operation is that of identifier and is an l-value if postfix-expression is an l-value.<BR><BR><BR>In the second form, postfix-expression represents a pointer to a structure, union,or class, and identifier names a member of the specified structure, union, or class. The value is that of identifier and is an l-value. <BR>The two forms of member-selection expressions have similar effects. <BR><BR>In fact, an expression involving the member-selection operator (-&gt;) is a shorthand version of an expression using the period (.) if the expression before the period consists of the indirection operator (*) applied to a pointer value. Therefore, <BR><BR>expression -&gt; identifier<BR><BR>is equivalent to<BR><BR>(*expression) . identifier<BR><BR>when expression is a pointer value.<BR><BR>Example<BR><BR>In the following example, the structure Dates and one object, myDates, is declared. The members of the myDates object are initialized with values for the beginning of 1995.<BR><BR>// Example of the structure operator<BR>struct Dates {<BR>&nbsp;&nbsp; CString&nbsp;&nbsp;&nbsp;&nbsp;sGregorian;<BR>&nbsp;&nbsp; int&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;nJulian;<BR>};<BR>Dates myDates;<BR>Dates.nJulian = 1;<BR>Dates.sGregorian = "01/01/95";<BR><BR>摘自《MSDN》<BR>
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回复者：iamhere 回复日期：2003-08-26 09:28:05
<br>内容：-&gt;是用作结构（struct）、联合（union）或者类（class）指针对其成员的引用，<BR>如果非指针，则是使用.
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<font color=red>答案被接受</font><br>回复者：张庆芳 回复日期：2003-08-26 09:28:26
<br>内容：我说简单些：<BR>－＞前面的应该是指向对象的指针，－＞后面的应该是该对象的属性，或者是该对象的方法。<BR>
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回复者：Fe 回复日期：2003-08-26 09:47:08
<br>内容：谢谢
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