大约有 45,000 项符合查询结果（耗时：0.0299秒） [XML]
Why does Java's hashCode() in String use 31 as a multiplier?
... for 31 since 33 is not a prime:
Of the remaining
four, I'd probably select P(31), as it's the cheapest to calculate on a RISC
machine (because 31 is the difference of two powers of two). P(33) is
similarly cheap to calculate, but it's performance is marginally worse, and
33 is composit...
Is std::vector so much slower than plain arrays?
... created. What happens if we change Pixel to:
struct Pixel
{
unsigned char r, g, b;
};
Result: about 10% faster. Still slower than an array. Hm.
# ./vector
UseArray completed in 3.239 seconds
UseVector completed in 5.567 seconds
Idea #4 - Use iterator instead of loop index
How about usin...
How to use sed to replace only the first occurrence in a file?
... then only looked for starting on the next line. Therefore, both lines are selected in this case, and the s/foo/bar/ substitution is performed on both of them.
sed '1,/foo/ s//bar/' <<<$'1foo\n2foo\n3foo' fails: with sed: first RE may not be empty (BSD/macOS) and sed: -e expression #1, char...
Splitting String with delimiter
...
Oh, and be careful if you're splitting on certain characters like a pipe |. You will need to escape the char stackoverflow.com/questions/3842537/…
– Snekse
Dec 23 '15 at 17:19
...
In-memory size of a Python structure
...
@AlexMartelli Hi Alex! .. Why minimum size of a char in python is 25 bytes. >>> getsizeof('a') gives 25 and >>> getsizeof('ab') gives 26 `
– Grijesh Chauhan
Jan 17 '13 at 5:13
...
How to check if a String contains only ASCII?
The call Character.isLetter(c) returns true if the character is a letter. But is there a way to quickly find if a String only contains the base characters of ASCII?
...
Best practices for circular shift (rotate) operations in C++
...lude <stdint.h> // for uint32_t
#include <limits.h> // for CHAR_BIT
// #define NDEBUG
#include <assert.h>
static inline uint32_t rotl32 (uint32_t n, unsigned int c)
{
const unsigned int mask = (CHAR_BIT*sizeof(n) - 1); // assumes width is a power of 2.
// assert ( (c<...
How do pointer to pointers work in C?
...his case, if this is the only occurrence of "hello" in memory then,
const char *c = "hello";
... defines c to be a pointer to the (read-only) string "hello", and thus contains the value 63. c must itself be stored somewhere: in the example above at location 58. Of course we can not only point to ...
VC/Linux C++ 递归访问目录下所有文件 - C/C++ - 清泛网 - 专注C/C++及内核技术
... C++ 递归访问目录下所有文件VC函数，部分代码如下：find(char * lpPath){ char szFind[MAX_PATH]; WIN32_FIND_DATA FindFileData; strcpy(sz...VC函数，部分代码如下：
find(char * lpPath)
{
char szFind[MAX_PATH];
WIN32_FIND_DATA FindFileData;
strcpy...