AnsiString::c_str
Returns the AnsiString converted to null-terminated character array.
char* __fastcall c_str() const;
Description
c_str returns a pointer a null-terminated character array containing the same characters as the AnsiString. If the AnsiString is unassigned, c_str returns an empty string (?).
Usually, the value returned by c_str points to the internal character array referenced by the data property. This pointer is valid until the string is next modified (for example when the SetLength method is called or the AnsiString goes out of scope). However, if the internal array is NULL, c_str returns a pointer to a string literal. 
The c_str method is intended primarily for reading the value of the AnsiString. To modify the strings value, use the [] operator or AnsiString methods such as Insert and Delete.

AnsiString c_str() example
AnsiString::c_str() returns a non const temporary pointer to the internal string buffer in the AnsiString object. The pointer is invalid once the statement in which it is used has finished executing. That is,don't do something like this:
   char* cp = Edit1->Text.c_str();
   char* cp2 = strtok( cp, " \t\n" ); // cp may no longer be valid
If you need a persistent pointer, you MUST copy the string into its own buffer:
   char* cp = new char[ Edit1->Text.Length()   1 ];
   strcpy( cp, Edit1->Text.c_str() );

(3)結論(我依照文件及實驗的結果做的推論)
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