Common Data Conversion in VC development database applications

Writing database programs with VC will inevitably encounter the conversion problem between the _ bstr_t, cstring, and ctime types, which is a headache. This morning, we finally solved the problem of cstring and ctime type conversion.

// Ctime --> cstring
Ctime T;
T = ctime: getcurrenttime ();
Cstring Sur;
Sur. Format ("% s", T. Format ("% Y-% m-% d "));
MessageBox (SUR );

// Long --> cstring
Long;
Cstring B;
B. Format ("% lD", );

// Double ---> cstring
Double;
Cstring B;
B. Format ("% F", );

// Cstring --> ctime

Cstring Sur;
Sur = "2006-08-09 ";
Coledatetime time1;
Time1.parsedatetime (SUR );
Systemtime receivime;
Varianttimetosystemtime (time1, & systime );
Ctime TM (systime );
M_time = TM;
Updatedata (false );
 

Conversion between cstring, Int, and float.

1. Int <-> cstring

1) int-> cstring

Int n = 1;

Cstring STR;

Str. Format ("% d", N );

2) cstring-> int

Cstring STR = "1 ";

Int n = atoi (Str. getbuffer (0 ));

2. char * And cstring

1) char *-> cstring

Char SZ [128];

Cstring STR;

Str. Format ("% s", SZ );

2) cstring-> char *

Cstring STR;

Int nlength = Str. getlength ();

Char * SZ = new char [nlength];

SZ = Str. getbuffer (0 );

3. Float <-> cstring1) float-> cstring

Float F = 0.0;

Cstring STR;

Str. Format ("% F", F );

2) cstring-> float

Cstring STR = "0.0 ";

Float F = atof (Str. getbuffer (0 ));

The first parameter of the format function is the type of the number to be converted.