CString类所有成员函数详解.doc

CString类所有成员函数详解
2009-03-27 10:53
CString类所有成员函数详解
VC里CString是我们最常用的类之一,我们觉得对它很熟悉了,可是你知道它的所有用法吗?
还是系统的学习一下吧,认真看完本文就OK了。
下面开始:
CString::Compare
pare( LPCTSTR lpsz ) const;
返回值字符串一样返回0
         小于lpsz 返回-1
         大于lpsz 返回1
         区分大小字符
         CString s1( "abc" );
CString s2( "abd" );
ASSERT( pare( s2 ) == -1 );
ASSERT( pare( "abe" ) == -1 );
CString::CompareNoCase
pareNoCase( LPCTSTR lpsz ) const;
返回值字符串一样返回0
        小于lpsz 返回-1
        大于lpsz 返回1
        不区分大小字符
CString::Collate
int Collate( LPCTSTR lpsz ) const;
同CString::Compare
CString::CollateNoCase
int CollateNocase( LPCTSTR lpsz ) const;
同CString::CompareNoCase
CString::CString
CString( );
CString( const CString& stringSrc );
CString( TCHAR ch, int nRepeat = 1 );
CString( LPCTSTR lpch, int nLength );
CString( const unsigned char* psz );
CString( LPCWSTR lpsz );
CString( LPCSTR lpsz );
例子最容易说明问题
CString s1;                    
CString s2( "cat" );             
CString s3 = s2;                
CString s4( s2 + " " + s3 );       
CString s5( 'x' );                      // s5 = "x"
CString s6( 'x', 6 );                   // s6 = "xxxxxx"
CString s7((LPCSTR)ID_FILE_NEW);        // s7 = "Create a new document"
CString city = "Philadelphia";
CString::Delete
int Delete( int nIndex, int nCount = 1);
返回值是被删除前的字符串的长度
nIndex是第一个被删除的字符,nCount是一次删除几个字符。根据我实验得出的结果:当nCount>要删除字符串的最大长度(GetCount() - nIndex)时会出错,当nCount过大,没有足够的字符删除时,此函数不执行。
例子
CString str1,str2,str3;
char a;
str1 = "nihao";
str2 = "nIhao";
int x;
// int i=(str1 == str2);     
(2,3);
如果nCount(3) > GetCount() – nIndex (5-2)就会执行错误
CString::Empty
Void Empty( );
没有返回值清空操作;
例子
CString s( "abc" );
();
ASSERT( ( ) == 0 );
CString::Find
int Find( TCHAR ch ) const;
int Find( LPCTSTR lpszSub ) const;
int Find( TCHAR ch, int nStart ) const;
int Find( LPCTSTR lpszSub, int nStart ) const;
返回值不匹配的话返回-1; 索引以0 开始
        nStar 代表以索引值nStart 的字符开始搜索,
即为包含以索引nStart字符后的字符