Conversion between char *, string and cstring

 

1. Convert the cstring class to the char * (lpstr) Type

Method 1: use forced conversion. For example:
Cstring thestring ("this is a test ");
Lptstr lpsz = (lptstr) (lpctstr) thestring;
Method 2: Use strcpy. For example:

Cstring thestring ("this is a test ");
Lptstr lpsz = new tchar [thestring. getlength () + 1];
_ Tcscpy (lpsz, thestring );
Method 3: Use cstring: getbuffer. For example:

Cstring S (_ T ("this is a test "));
Lptstr P = S. getbuffer ();
// Add the code using P here

If (P! = NULL) * P = _ T ('\ 0 ');
S. releasebuffer ();
// Release immediately after use, so that other cstring member functions can be used.

Cstring STR = "abcdef ";
Char * pbuf = STR, getbuffer (0 );
Str. releasebuffer ();

2. Convert string to char *

String is one of the C ++ standard libraries, which encapsulates string operations.
Convert string to char *
There are three methods:
1. Data (), returns a string array without "\ 0"

For example:
String STR = "ABC ";
Char * P = Str. Data ();
2. c_str returns a string array with "\ 0"

For example, string STR = "gdfd ";
Char * P = Str. c_str ();
3 copy
For example
String STR = "hello ";
Char P [40];
Str. Copy (p, 5, 0); // here, 5 represents the number of characters to be copied, and 0 represents the copy position.
* (P + 5) = '\ 0'; // You must manually add the Terminator.
Cout <P;

Iii. String Conversion to other data types

Temp = "123456 ";
1) Short INTEGER (INT)
I = atoi (temp );
2) long integer (long)
L = atol (temp );
3) floating point (double)
D = atof (temp );
String s; D = atof (S. c_str ());
4) BSTR variable
BSTR bstrvalue =: sysallocstring (L "programmer ");
... // Complete the use of bstrvalue
Sysfreestring (bstrvalue );
5) ccombstr variable
Ccombstr variables can be directly assigned values.
Ccombstr bstrvar1 ("test ");
Ccombstr bstrvar2 (temp );
6) _ bstr_t variable
_ Bstr_t type variables can be directly assigned values
_ Bstr_t bstrvar1 ("test ");
_ Bstr_t bstrvar2 (temp );

Iv. Convert char * to string

If you want to put a char
Convert to string,
AvailableString S (char *); 

V. String
Convert cstring

Cstring. Format ("% s", String. c_str ());

Vi. Char
Convert cstring
Cstring. Format ("% s", char *);

VII. cstring-> string

String S (cstring. getbuffer ());
Releasebuffer () is required after getbuffer (). Otherwise, no space occupied by the buffer is released.

8. cstring mutual int Conversion

Converts a character to an integer. You can use atoi, _ atoi64, or atol.
To convert a number to a cstring variable, you can use the format function of cstring. For example
Cstring S;
Int I = 64;
S. Format ("% d", I)