Int char * string float cstring common Conversions

 

Int to char */Char []
Method:
Int num = 0;
Char temp [64];
Sprintf (temp, "% d", num );
Or
Int number = 123456;
Char string [25];
ITOA (number, String, 10); // 10 converts the base number of a number (in hexadecimal notation). 10 is

Converts a number in decimal format. It can also be 2, 8, 16, and so on.

 

Char * to string
Method:
Char temp [64];
String str1 (temp );
You can only initialize or assign values. It is best to use assign () instead of initialization ().
String & assign (const char * s); values are assigned by string s of the C type.

Or
Char temp [64];
String str1;
Str1 = temp;

 

Int to string
Use int to char */Char [] and char * to string.

String to char *
Method:
Char C [20];
String S = "1234 ";
Strcpy (C, S. c_str ());
The following method is not recommended.
String STR;
Char * temp;
Temp = filename. c_str ()
// C finally points to the content of spam, because the S object is destructed and its content is processed

 

 

String to int
Method:

String source = "1412 ";
Int result = 0;

// Use convert. toint32 (string value );
Result = convert. toint32 (source );

// Use int32.parse (string value );
Result = int32.parse (source );

// Use int32.tryparse (string S, out int result );
Int32.tryparse (source, out result );
The three differences are as follows:

Http://blog.csdn.net/clever_yang/archive/2009/03/20/400800

5. aspx

① Cstring to float
Cstring strtemp = "11.22 ";
Float m_drundistance = atof (strtemp); // converts strtemp to float
Error message:
. Cpp (815): Error c2664: 'atof ': cannot convert parameter 1 from 'cstring' to 'const char *'
Cause: Double atof (const char * nptr );
Solution Analysis: Convert cstring to char *: Use the getbuffer method of the cstring object, so m_drundistance = atof (strtemp. getbuffer (0); an error occurs:
CPP (815): Error c2664: 'atof ': cannot convert parameter 1 from 'wchar _ T *' to 'const char *'
It indicates that the above method does not work, so use
Method 1: forced conversion of lpctstr (though not recommended)
M_drundistance = atof (char *) lpctstr (strtemp ));
The test is successful and no data is lost after the test.
Method 2: Use the uses_conversion Macro. However, this macro cannot be used in a Large Loop body or a large function, because it can be released only when the function is completed, so there is a stack overflow problem.
Uses_conversion
M_drundistance = atof (T2A (strtemp ));
Method 3: Convert the cstring type to char * and then return it to atof. (This method is feasible)
Char STR [1024];
Cstring str2;
Widechartomultibyte (cp_acp, 0, str2,-1, STR, 1024, null, null );
Float FF = atof (STR );

 

② Cstring to int
// Convert the id from cstring to int
Cstring tempfield1;
Int ruleid = _ tstoi (tempfield1 );
// Convert the id from Char to int
Char tempfield1 [10];
Ruleid = atoi (tempfield1 );

③ Cstring to char *
Method 1. widechartomultibyte () function
Cstring str2;
Char STR [1024];
Widechartomultibyte (cp_acp, 0, str2,-1, STR, 1024, null, null );
Method 2: T2A ()
Uses_conversion
Char * STR = T2A (strtemp );
Method 3: forced conversion
Char * STR = (char *) lpctstr (strtemp );

④ Convert char *, Int, float, and Other types to cstring
This type of conversion is easier. You can convert it using formats such as format or sprintf.
For example, int K = 10;
Cstring strtype;
Strtype. Format (_ T ("% d", delimiter? K ));
Char * Ch;
Cstring STR;
Ch = (lpstr) (lpctstr) STR;
STR = "Good! ";
Sprintf (CH, "% s", (lptstr) (lpctstr) Str );

 

4. Security
Cstring> string> char *;
5. Flexibility
Cstring> string> char *;
6. Portability
Char * = string> cstring;