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L και ULL, τι διαολο ειναι αυτα??


Krokodilos

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Δημοσ.

Σε ενα κωδικα C που διαβαζω βλεπω τους ορισμους:

 

>
#define WIDTH	0x01010101L
uint64_t K= 0xFF8800000FFFULL;
uint64_t Τ= 0x8800000ULL;

 

Τι διαολο ειναι τα L και ULL στο τελος των αριθμων?

Για ποιο σκοπο υπαρχουν? Και δεν υπαρχουν και στην βοηθεια του Visual Studio(MSDN).:cry:

Δημοσ.

Το L στο τέλος ενός αριθμού δηλώνει LONG.

Το UL δηλώνει UNSIGNED LONG.

Το ULL δεν μου θυμίζει κάτι

 

--edit προσθήκη τμήματος manual--

 

 

>
2.4.4 Literals
A literal is a source code representation of a value.
literal:
boolean-literal
integer-literal
real-literal
character-literal
string-literal
null-literal
2.4.4.1 Boolean literals
There are two boolean literal values: true and false.
boolean-literal:
true
false
The type of a boolean-literal is bool.
2.4.4.2 Integer literals
Integer literals are used to write values of types int, uint, long, and ulong. Integer literals have two possible forms: decimal and hexadecimal. 
integer-literal:
decimal-integer-literal
hexadecimal-integer-literal
decimal-integer-literal:
decimal-digits   integer-type-suffixopt
decimal-digits:
decimal-digit
decimal-digits   decimal-digit
decimal-digit:  one of
0  1  2  3  4  5  6  7  8  9
integer-type-suffix:  one of
U  u  L  l  UL  Ul  uL  ul  LU  Lu  lU  lu
hexadecimal-integer-literal:
0x   hex-digits   integer-type-suffixopt
0X   hex-digits   integer-type-suffixopt
hex-digits:
hex-digit
hex-digits   hex-digit
hex-digit:  one of
0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F  a  b  c  d  e  f
The type of an integer literal is determined as follows:
·	If the literal has no suffix, it has the first of these types in which its value can be represented: int, uint, long, ulong.
·	If the literal is suffixed by U or u, it has the first of these types in which its value can be represented: uint, ulong.
·	If the literal is suffixed by L or l, it has the first of these types in which its value can be represented: long, ulong.
·	If the literal is suffixed by UL, Ul, uL, ul, LU, Lu, lU, or lu, it is of type ulong.
If the value represented by an integer literal is outside the range of the ulong type, a compile-time error occurs.
As a matter of style, it is suggested that “L” be used instead of “l” when writing literals of type long, since it is easy to confuse the letter “l” with the digit “1”.
To permit the smallest possible int and long values to be written as decimal integer literals, the following two rules exist:
·	When a decimal-integer-literal with the value 2147483648 (231) and no integer-type-suffix appears as the token immediately following a unary minus operator token (§7.6.2), the result is a constant of type int with the value −2147483648 (−231). In all other situations, such a decimal-integer-literal is of type uint.
·	When a decimal-integer-literal with the value 9223372036854775808 (263) and no integer-type-suffix or the integer-type-suffix L or l appears as the token immediately following a unary minus operator token (§7.6.2), the result is a constant of type long with the value −9223372036854775808 (−263). In all other situations, such a decimal-integer-literal is of type ulong.

 

 

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