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When the compiler will found KEYPAD_NO_NEW_DATA string in your files will replace it with the ASCII code for - (just the last byte if are more then 1, due the type cast to char).
When the compiler will found KEYPAD_NO_NEW_DATA string in your files will replace it with the ASCII code for - (just the last byte if are more then 1, due the type cast to char).
I still not understand what you mean just the last byte if are more then 1, due the type cast to char can you explain clearly bcause i am beginner.. .....
Why they put (char) and '-', what they define?? If they #define TRAN_BUFFER_LENGTH 20, i know the TRAN_BUFFER_LENGTH is 20
What the different between: #define TRAN_BUFFER_LENGTH 20 and int TRAN_BUFFER_LENGTH = 20
#define is use just to easy modify and understand your code. Practical when you #define A B , at compile time the A will be replaced with B. Now how complicated is the #define is a code writer option.
first:
'-' means the ASCII code for the character - , that is 0x2D (or something near). If the ASCII codes are coded in integers, that means that you can have 65535 ASCII codes, then the type cast (char) will select only 0x2D, and replace your definition in the code with 0x2D, instead of 0x002D. If your ASCII code is coded on 1 byte (that means max 256 ASCII codes) then your type cast to char is redundant and don't do any harm.
second:
the diference betwen #define TRAN_BUFFER_LENGHT 20 and int TRAN_BUFFER_LENGHT = 20 is that:
in first case whenever TRAN_BUFFER_LENGHT is found in your code will be replaced with 20 at compile time
in the second case you define ("create" to be less ambiguos) an integer variable call TRAN_BUFFER_LENGHT and initialise to value 20
Q1)
I already understand it already.. which mean that..
if we put (char) it just only 8bit=256=>0xFF, so in ASCII the - is 0x2D then the TRAN_BUFFER_LENGHT is define as a 0x2D = -, am i right??
if we put (int) it have 16bit=65535=>0xFFFF, then the TRAN_BUFFER_LENGHT is define as a 0x002D = -, am i right??
Q2)
In what condition we must put (int) / (long)..? Since the ASCII just only use 8bit(char)...
Q3)
I understand that the int TRAN_BUFFER_LENGTH = 20 is define TRAN_BUFFER_LENGTH as a int and it can define between this 0 - 65535 value. If we compare with #define TRAN_BUFFER_LENGTH 20 it still given us the same result am i right...? Can we alway use define ... define... and define... all the ... eg. #define BUFFER_LENGTH 20, #define BUFFER 30 and so on..?
Yes, but the variable definition (int TRAN_BUFFER_LENGTH = 20) can be change at run time. The #define is seen as a constant.
No, we can't use always define.. define.., with the exception (unlikely) that your code don't use variables.
see h**p://www.unicode.org/ . The characters are coded on 16 bits.
Q3)
Yes, but the variable definition (int TRAN_BUFFER_LENGTH = 20) can be change at run time. The #define is seen as a constant.
No, we can't use always define.. define.., with the exception (unlikely) that your code don't use variables.
Q1,2)
I understand already..., there are many type of code ASCII, UCS, UTF.. and so on.
Type Each character
encoded as Notes
7-bit a single 7-bit quantity example: ISO 646
8-bit G0/G1 a single 8-bit quantity with constraints on use of C0 and C1 spaces
8-bit a single 8-bit quantity with no constraints on use of C1 space
8-bit EBCDIC a single 8-bit quantity with the EBCDIC conventions rather than ASCII conventions
16-bit (UCS-2) a single 16-bit quantity within a code space of 0..FFFF
32-bit (UCS-4) a single 32-bit quantity within a code space 0..7FFFFFFF
32-bit (UTF-32) a single 32-bit quantity within a code space of 0..10FFFF
16-bit DBCS process code a single 16-bit quantity example: UNIX widechar implementations of Asian CCS's
32-bit DBCS process code a single 32-bit quantity example: UNIX widechar implementations of Asian CCS's
If we use ASCII it just the 8bit only, if we use UCS then it is 16bit but the program is difference writing already, not that simple #define KEYPAD_NO_NEW_DATA (char) '-' already... am i right?
Q3)
Yes, but the variable definition (int TRAN_BUFFER_LENGTH = 20) can be change at run time
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