Characters and string handling in C (ANSI characters and Unicode characters)

As we know, the C language USES the char data type to represent an 8-bit ANSI character. When a string is declared in the code by default, the C compiler converts the characters in the string into an array of 8-bit char data types:

// An 8-bit character

char c = 'A';

// An array of 99 8-bit character and 8-bit terminating zero

char szBuffer[100] = "A String";

Microsoft's C/C++ compiler defines a built-in data type, wchar_t, which represents a 16-bit Unicode (utf-16) character. The compiler defines this parameter type only when it specifies the /Zc:wchar_t compiler switch.

Declare Unicode characters and strings as follows:

// A 16-bit character

wchar_t c= L'A';

// An array up to 99 16-bit characters and a 16-bit terminating zero

wchar_t szBuffer[100] = L"A String";

The uppercase L before the string tells the compiler that the string should compile a Unicode string.

In addition, when writing code, you can use ANSI or Unicode characters/strings to make it compilable. Winnt.h defines the following types and macros:

#ifdef UNICODE

typedef WCHAR TCHAR, *PTCHAR, PTSTR;

typedef CONST WCHAR *PCTSTR;

#define __TEXT(quote) L##quote

#else

typedef CHAR TCHAR, *PTCHAR, PTSTR;

typedef CONST CHAR *PCTSTR;

#define __TEXT(quote) quote

#endif

#define TEXT(quote) __TEXT(quote)

Using these types and macros to write code can be compiled using either ANSI or Unicode characters, as shown below:

// If UNICODE define, a 16-bit character; else an 8-bit character

TCHAR c = TEXT('A');

// If UNICODE define, an array of 16-bit character; else 8-bit character

TCHAR szBuffer[100] = TEXT("A String");

That's all for this article and I hope you enjoy it.