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Bytes of a string in Java
...
A string is a list of characters (i.e. code points). The number of bytes taken to represent the string depends entirely on which encoding you use to turn it into bytes.
That said, you can turn the string into a byte array and then look at its si...
Storing sex (gender) in database
...,147,483,648 to 2,147,483,647
BIT 1 (2 if 9+ columns) 2 (0 and 1)
CHAR(1) 1 26 if case insensitive, 52 otherwise
The BIT data type can be ruled out because it only supports two possible genders which is inadequate. While INT supports more than two options, it takes...
Pointer arithmetic for void pointer in C
When a pointer to a particular type (say int , char , float , ..) is incremented, its value is increased by the size of that data type. If a void pointer which points to data of size x is incremented, how does it get to point x bytes ahead? How does the compiler know to add x to value of ...
#pragma pack effect
...example, given 4-byte integers and the following struct:
struct Test
{
char AA;
int BB;
char CC;
};
The compiler could choose to lay the struct out in memory like this:
| 1 | 2 | 3 | 4 |
| AA(1) | pad.................. |
| BB(1) | BB(2) | BB(3) | BB(4) |
| CC(1) | pa...
Calling constructors in c++ without new
...new object on the stack by calling a constructor of the format Thing(const char*).
The second one is a bit more complex. It essentially does the following
Create an object of type Thing using the constructor Thing(const char*)
Create an object of type Thing using the constructor Thing(const Th...
best practice to generate random token for forgot password
...es DATETIME,
PRIMARY KEY(id)
);
... you need to add one more column, selector, like so:
CREATE TABLE account_recovery (
id INTEGER(11) UNSIGNED NOT NULL AUTO_INCREMENT
userid INTEGER(11) UNSIGNED NOT NULL,
selector CHAR(16),
token CHAR(64),
expires DATETIME,
PRIMARY K...
How can I truncate a datetime in SQL Server?
...umbled on this when I tried to truncate a date to the first of the month: SELECT DATEADD( m, 0, DATEDIFF( m, 0, GETDATE( ) ) ) does not work, but SELECT DATEADD( m, DATEDIFF( m, 0, GETDATE( ) ), 0 ) does. At least, this is what I see in 2008R2.
– Kelly Cline
...
How do I find out which computer is the domain controller in Windows programmatically?
...
@DorkyEngineer how about marking this as your selected answer?
– ErikE
Jan 4 '13 at 2:44
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C/C++中的段错误（Segmentation fault） - C/C++ - 清泛网 - 专注C/C++及内核技术
...ce
例子2：
Code:
#include <stdio.h>
int main(){
char *p;
p = NULL;
*p = 'x';
printf("%c", *p);
return 0;
}
很容易发现，这个例子也是试图往内存地址0处写东西。
这里我们通过gdb来查看段错误所在的行
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Efficient Algorithm for Bit Reversal (from MSB->LSB to LSB->MSB) in C
... Bit Twiddling Hacks page:
Fastest (lookup table):
static const unsigned char BitReverseTable256[] =
{
0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF...