C语言取模

int example = 0xffffffff;
int *p = &example;
 
example%0x100;
*p%0x100;
0xffffffff%0x100;

求大神指点，这3个表达式的第一个和第二个为什么结果和第三个不一样 C
[解决办法]
没调试。
但估计就是有符号数，无符号数的问题。
前面的int是有符号数。0xffffffff好像是-1的补码吧，基本上忘完了。。。。。
后面的0xffffffff怎么说呢，算是常数，可能当成无符号数来处理了。或者做64位数处理了。

跟踪一下就清楚了。

是否会跟踪？
[解决办法]

unsigned int example = 0xffffffffu;
unsigned int *p = &example;
  
example%0x100u;
(*p)%0x100u;
0xffffffffu%0x100u;

常量也有类型。
对负数取余，结果未定。

C++ Integer Constants
Integer constants are constant data elements that have no fractional parts or exponents. They always begin with a digit. You can specify integer constants in decimal, octal, or hexadecimal form. They can specify signed or unsigned types and long or short types.

Syntax

integer-constant :

decimal-constant integer-suffixopt
octal-constant integer-suffixopt
hexadecimal-constant integer-suffixopt
'c-char-sequence'

decimal-constant :

nonzero-digit
decimal-constant digit

octal-constant :

0
octal-constant octal-digit

hexadecimal-constant :

0x hexadecimal-digit
0X hexadecimal-digit
hexadecimal-constant hexadecimal-digit

nonzero-digit : one of

1 2 3 4 5 6 7 8 9

octal-digit : one of

0 1 2 3 4 5 6 7

hexadecimal-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

integer-suffix :

unsigned-suffix long-suffixopt
long-suffix unsigned-suffixopt

unsigned-suffix : one of

u U

long-suffix : one of

l L

64-bit integer-suffix :

i64

To specify integer constants using octal or hexadecimal notation, use a prefix that denotes the base. To specify an integer constant of a given integral type, use a suffix that denotes the type.

To specify a decimal constant, begin the specification with a nonzero digit. For example:

int i = 157; // Decimal constant
int j = 0198; // Not a decimal number; erroneous octal constant
int k = 0365; // Leading zero specifies octal constant, not decimal

To specify an octal constant, begin the specification with 0, followed by a sequence of digits in the range 0 through 7. The digits 8 and 9 are errors in specifying an octal constant. For example:

int i = 0377; // Octal constant
int j = 0397; // Error: 9 is not an octal digit

To specify a hexadecimal constant, begin the specification with 0x or 0X (the case of the “x” does not matter), followed by a sequence of digits in the range 0 through 9 and a (or A) through f (or F). Hexadecimal digits a (or A) through f (or F) represent values in the range 10 through 15. For example:

int i = 0x3fff; // Hexadecimal constant
int j = 0X3FFF; // Equal to i

To specify an unsigned type, use either the u or U suffix. To specify a long type, use either the l or L suffix. For example:

unsigned uVal = 328u; // Unsigned value

long lVal = 0x7FFFFFL; // Long value specified
// as hex constant
unsigned long ulVal = 0776745ul; // Unsigned long value