(I. Overview
CString string and a string are template class, a standard string string class template class (STL) defined in the C ++ standard has been included;
CString (typedef CStringT <TCHAR, StrTraitMFC <TCHAR >> CString) is most commonly used in Visual C ++ string class, the class inherits from CSimpleStringT, MFC and ATL in the main application program, the data type has mainly char (applied to the ANSI), wchar_t (unicode), TCHAR (ANSI to unicode available);
char * is the most commonly used C programming string pointer, generally '\ 0' for the end flag;
(B) construction
string is convenient, may be constructed from almost all the strings, including CString and char *;
CString followed, may be constructed from a number string from the basic variables, including char * and the like;
char * has no constructor, it can only be assigned;
For example:
char * psz = "joise";
CString cstr( psz );
string str( cstr );
(C) operator overloading
a) operator=
string is the most convenient, almost all the strings directly assignments, including CString and char *;
CString followed directly with some basic string assignment, including char * and the like;
char * pointer can only be assigned by, and is a very dangerous operation, it is recommended to use strcpy or memcpy, and when it was declared char * If no initial value is recommended to set to NULL, in order to avoid dangling pointer, make you crazy;
For example:
char *psz = NULL;
psz = new char [10]; // Of course, the above written directly char * psz = new char [10]; the same is
memset( psz, 0, 10 );
strcpy( psz, “joise” );
CString cstr;
cstr = psz;
string str;
str = psz;
str = cstr;
delete []psz;
b) operator+
CString string and almost directly with an addition char *, but not with each other using the + operator, i.e. string str = str + cstr is illegal, must be converted to char *;
char * + No operation, only the two pointers strcat together;
For example:
char * psz = "joise";
CString cstr = psz;
cstr = cstr + psz;
string str = psz;
str str = str + + PSZ;
strcat( psz, psz );
strcat (psz, cstr); // legal
strcat (psz, str); // illegal Thus, CString be automatically converted to const char *, not the string
c) operator +=
string is the most powerful, almost all of the + = string variables, including CString and char *;
CString followed, some may be carried out substantially from the string variable + =, comprising char * and the like;
char * no + = operator, using only the two pointers strcat together;
d) operator[]
CString best, when cross-border assertion will throw an exception;
char * string with the index out of bounds undefined;
For example:
char * psz = "joise";
CString cstr = psz;
cout << cstr[8];
string str = psz;
cout << str[8];
cout << psz[8];
e) operator ==, operator! =, operator>, operator>, operator> =, antagonist <=
And it can not be compared between CString string, but can be compared with the char *, and the comparison is a value, instead of the address;
cout << ( psz == cstr );
cout << ( psz == str );
cout << ( str == psz );
cout << (cstr == psz); above are // code returns 1
(Iv) common algorithms
a) Find
Role char * string CString
to find the specified value strchr
strstr
strrstr
strspn the Find the Find
the first matching value fild_first_of FindOneOf
from behind to start looking ReserveFind
specified matching mode find_if
NOTE: find_if the value is substituted into the range one by one until the function returns true match
b) compare
Char * string CString action
to find the specified value (case sensitive) strcmp
a strncmp
of strcoll
_strncoll operator <
operator>
operator <=
operator> =
operator ==
operator! = The Collate
Compare
to find the specified value (not case sensitive) _stricmp
_strnicmp
_stricoll
_strnicoll CollateNoCase
CompareNoCas
NOTE: If the return value <0 is less than the preceding value of the back, and vice versa
c) Replace
Role char * string CString
to find the specified value _strset
_strnset
the replace
replace_copy
replace_copy_if
replace_if Replace
d) insertion
Role char * string CString
to find the specified value insert Insert
e) increasing effect char * string CString
dynamic value added strcat push
append Append
AppendChar
AppendFormat
f) taken
Char * string CString effect
obtained by the subscript value operation part substr Left
Mid
Right
Truncate
g) removed
Role char * string CString
remove a portion of the value remove Remove
to remove the blank value RemoveBlanks
Note: This is the ATL provides non-C functions remove_if Trim
TrimLeft
TrimRig
h) change case
Role char * string CString
to change the case _strlwr
_strupr MakeLower
MakeUpper
i) converting other types
Role char * string CString
into digital atoi
supp
atof Format
into c_str * char
GetBuffer
GetBufferSetLen
j) format
Role char * string CString
format sprintf Format
k) length to give
Char * string CString effect
obtained length strlen length GetLength
obtained size size GetAllocLength
l) is empty is determined
Char * string CString role of
determining whether is empty or == NULL is determined whether the first character is '\ 0' empty IsEmpty
m) resizing
Char * string CString effect
resizing realloc
new new Assertion in GetBufferSetLength a resize
n) the release of resources
Role char * string CString
release free
delete (delete[]) ReleaseBuffer
ReleaseBufferSetLength
(E) Security>
CString > string > char*；
(Vi) Flexibility
CString > string >char*；
(Vii) portability
char* = string > CString
f) taken
Char * string CString effect
obtained by the subscript value operation part substr Left
Mid
Right
Truncate
g) removed
Role char * string CString
remove a portion of the value remove Remove
to remove the blank value RemoveBlanks
Note: This is the ATL provides non-C functions remove_if Trim
TrimLeft
TrimRig
h) change case
Role char * string CString
to change the case _strlwr
_strupr MakeLower
MakeUpper
i) converting other types
Role char * string CString
into digital atoi
supp
atof Format
into c_str * char
GetBuffer
GetBufferSetLen
j) format
Role char * string CString
format sprintf Format
k) length to give
Char * string CString effect
obtained length strlen length GetLength
obtained size size GetAllocLength
l) is empty is determined
Char * string CString role of
determining whether is empty == NULL is determined whether or the first character is a '\ 0' empty the IsEmpty
m) resizing
Char * string CString effect
resizing realloc
new new Assertion in GetBufferSetLength a resize
n) the release of resources
Role char * string CString
release free
delete (delete[]) ReleaseBuffer
ReleaseBufferSetLength
(e) Security>
CString > string > char*；
(Vi) Flexibility
CString > string >char*；
(Vii) portability
char* = string > CString
Reproduced in: https: //www.cnblogs.com/shelvenn/archive/2008/01/11/1035184.html