VC ++ basic knowledge

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• Decimal to hex
• HEX to decimal
• Decimal to time
• String to hex
• HEX to cstring
• Colevariant to cstring
• Cstring to Char pointer
• Char pointer to cstring
• Double to cstring including the fractional part
• Double to cstring
• Cstring to double
• Cstring to lpcstr
• Cstring to lpstr
• Cstring to wchar *
• Lptstr to lpwstr
• String to BSTR
• Cstring to BSTR
• _ Bstr_t to cstring
• Char array to integer
• Char array to float
• Char pointer to double
• Char pointer to integer
• Char pointer to long
• Char * To BSTR
• Float to word and vice versa

1. The symbols are not described as follows: Scope delimiters;. Category class members;-> pointers.

2. wide range of types:

Lpstr 32-bit pointer, pointing to a string
The 32-bit pointer to a constant string. This string can be transplanted to Unicode and DBCS (dubyte Character Set) and points to the const type string pointer per character 16 bytes.
Lptstr 32-bit pointer, pointing to a string, which can be transplanted to Unicode and DBCS (dubyte Character Set), pointing to the pointer of a string of 16 bytes per character.
The 32-bit pointer to a constant string and a pointer to a const string of every 8 bytes.
Unicode string ending with \ 0, that is, double byte

 

Windows data types are described as follows:
Windows Data Types
Lpcstr: pointer to a constant null-terminated string of 8-bit windows (ANSI) characters.
Lpctstr: An lpcwstr if Unicode is defined, an lpcstr otherwise.
Lpcwstr: pointer to a constant null-terminated string of 16-bit Unicode characters.
Lptstr: An lpwstr if Unicode is defined, an lpstr otherwise.
Lpstr: pointer to a null-terminated string of 8-bit windows (ANSI) characters.
Lpwstr: pointer to a null-terminated string of 16-bit Unicode characters.

 

Char 8bit ANSI character
Wchar 16bit Unicode Character
If tchar defines Unicode macros (# def Unicode), tchar is equivalent to wchar. If no Unicode macro is defined,
Tchar is equivalent to Char

 

Lpcstr: equivalent to const char * read-only ANSI string pointer
Cstring: the class for packaging strings in MFC, which can be ANSI or uncode.
Char * ANSI string pointer
Char [] ANSI character array, which can be used as a pointer string
Char is equivalent to Char, an ANSI character

 

L ("hello") indicates converting to a wide character to support Unicode

3. type conversion:

Decimal conversionsdecimal to hex

 
//Use _ ITOA () function and set Radix to 16.CharHexstring [10];IntNumber =30; ITOA (number, hexstring,16);//In hexstring is 1E.
 

HEX to decimal

 
//You can use strtol function and you can specify base.Char* Hexstring ="Abcdef";Char* P;IntNumber = strtol (hexstring, & P,16);//A function that does thisBoolHextodecimal (Char* Hexnumber, Int & number ){Char* Pstopstring; number = strtol (hexnumber, & pstopstring,16);Return(Bool) (Number! = Long_max );}
 

Decimal to time

Char* Dectotime (FloatFtime,Char* Sztime ){IntNhrs, Nmin, nsec; ftime * =3600; Nhrs = (Int) Ftime/3600; Nmin = (Int) (Ftime-nhrs *3600)/60; Nsec = (Int) (Ftime-nhrs *3600-Nmin *60); Wsprintf (sztime,"% 02d. % 02d. % 02d hrs. Min. Sec .", Nhrs, Nmin, nsec );ReturnSztime ;}
 

String conversionsstring to hex

Sscanf (String, % 04x, & your_word16 );//Where string = your string and//04 = length of your string and x = hex
 

HEX to cstring

 
Cstring STR;Unsigned CharWrite_buff [1]; Write_buff [0] = 0x01; Str. Format ("0x0% x", Write_buff [0]);
 

Colevariant to cstring

 
Cstring strtemp; colevariant var; Var ="Firstname"; Strtemp = var. bstrval; afxmessagebox (strtemp );
 

Cstring to Char pointer

Cstring mystring ="Abcdef";Char* Szmystring = (Char*) (Lpctstr) mystring;
 

 
Char* Pbuffer =New Char[1024]; Cstring strbuf ="Test"; Pbuffer = strbuf. getbuffer (Sizeof(Pbuffer ));
 

Char pointer to cstring

 
Char* Mystring ="12345"; CstringString= Mystring;
 

Double to cstring including the fractional part

Cstring strvalue, strint, strdecimal; Int Decimal, sign; Double Dvalue = 4 . 125 ; Strvalue = _ fcvt (dvalue, 6 , & Decimal, & sign ); //  Now decimal contains 1 because there is      //  Only one digit before. Strint = strvalue. Left (decimal ); //  Strint contains 4 Strdecimal = strvalue. mid (decimal ); //  Strdecimal contains 125. Cstring strfinalval; strfinalval. Format ( "  % S. % s" , Strint, strdecimal ); //  Strfinalval contains 4.125 

Double to cstring

 
Cstring strvalue;IntDecimal, sign;DoubleDvalue =123456789101112; Strvalue = _ ECVT (dvalue,15, & Decimal, & sign );
 

Cstring to double

 
Strvalue ="121110987654321"; Dvalue = atof (strvalue );
 

Cstring to lpcstr

Cstring str1 = _ T ("My string");IntNlen = str1.getlength (); lpcstr lpszbuf = str1.getbuffer (nlen );//Here do something with lpszbuf ...........Str1.releasebuffer ();
 

Cstring to lpstr

 
Cstring STR = _ T ("My string");IntNlen = Str. getlength (); lptstr lpszbuf = Str. getbuffer (nlen );//Here do something with lpszbuf ...........Str. releasebuffer ();
 

Cstring to wchar *

Cstring STR ="A string here"; Lpwstr lpszw =NewWchar [255]; Lptstr lpstr = Str. getbuffer (Str. getlength ());IntNlen = multibytetowidechar (cp_acp,0, Lpstr ,-1, Null, null); multibytetowidechar (cp_acp,0, Lpstr ,-1, Lpszw, nlen); afunctionuseswchar (lpszw );Delete[] Lpszw;
 

Lptstr to lpwstr

 
IntNlen = multibytetowidechar (cp_acp,0, Lptstr ,-1, Null, null); multibytetowidechar (cp_acp,0, Lptstr ,-1, Lpwstr, nlen );
 

String to BSTR

StringSs ="Girish"; BSTR _ bstr_home = a2bstr (ss. c_str ());
 

Cstring to BSTR

 
Cstring STR ="Whatever"; BSTR resultsstring = Str. allocsysstring ();
 

_ Bstr_t to cstring

# Include <Ansiapi. h># Include <Comdef. h>_ Bstr_t bstext ("Hai Bayram"); Cstring strname; w2a (bstext, strname. getbuffer (256),256); Strname. releasebuffer (); afxmessagebox (strname );CharSzfilename [256]; Getmodulefilename (null, szfilename,256); Afxmessagebox (szfilename );
 

Character arrayschar array to integer

CharMyarray [20];IntNvalue; nvalue = atoi (myarray );
 

Char array to float

 
CharMyarray [20];FloatFvalue; fvalue = atof (myarray );
 

Char pointer to double

 
Char* STR ="-343.23";DoubleDval; dval = atof (STR );
 

Char pointer to integer

 
Char* STR ="-343.23";IntIval; ival = atoi (STR );
 

Char pointer to long

Char* STR ="99999";LongLval; lval = atol (STR );
 

Char * To BSTR

 
Char* P ="Whatever"; _ Bstr_t BSTR = P;
 

Float to word and vice versa

FloatFvar; Word wvar; fvar =247.346; Wvar = (Word) fvar;//Converting from float to word.//The value in wvar wocould be 247Wvar =247; Fvar = (Float) Fvar;//Converting from word to float.//The value in fvar wocould be 247.00