strlen wcslen sizeof

strlen
the length of char (determined by a number of characters before null termination)

wcslen
the length of wide char
在winnt.h
定義
typedef WCHAR TCHAR, *PTCHAR;
typedef WCHAR TBYTE, *PTBYTE;

所以可用TCHAR去宣告變數 系統會轉成wide char

sizeof
the amount of the storage, in bytes, associated with a variable or a type.



Reference:
strlen()
VC知識庫文章
wcslen()