大约有 40,000 项符合查询结果（耗时：0.0321秒） [XML]
memcpy() vs memmove()
...or you risk undefined behaviour, while the memory in memmove can overlap.
char a[16];
char b[16];
memcpy(a,b,16); // valid
memmove(a,b,16); // Also valid, but slower than memcpy.
memcpy(&a[0], &a[1],10); // Not valid since it overlaps.
memmove(&a[0], &a[1],10); ...
“where 1=1” statement [duplicate]
...hould ignore it
No magic, just practical
Example Code:
commandText = "select * from car_table where 1=1";
if (modelYear <> 0) commandText += " and year="+modelYear
if (manufacturer <> "") commandText += " and value="+QuotedStr(manufacturer)
if (color <> "") command...
Undefined, unspecified and implementation-defined behavior
...t's look at a classic example:
#include <iostream>
int main()
{
char* p = "hello!\n"; // yes I know, deprecated conversion
p[0] = 'y';
p[5] = 'w';
std::cout << p;
}
The variable p points to the string literal "hello!\n", and the two assignments below try to modify tha...
What does the comma operator , do?
...ariables used in a for loop, and it gives the following example:
void rev(char *s, size_t len)
{
char *first;
for ( first = s, s += len - 1; s >= first; --s)
/*^^^^^^^^^^^^^^^^^^^^^^^*/
putchar(*s);
}
Otherwise there are not many great uses of the comma operator, although it i...
Create a temporary table in a SELECT statement without a separate CREATE TABLE
Is it possible to create a temporary (session only) table from a select statement without using a create table statement and specifying each column type? I know derived tables are capable of this, but those are super-temporary (statement-only) and I want to re-use.
...
PowerShell equivalent to grep -f
...
The -Pattern parameter in Select-String supports an array of patterns. So the one you're looking for is:
Get-Content .\doc.txt | Select-String -Pattern (Get-Content .\regex.txt)
This searches through the textfile doc.txt by using every regex(one pe...
What is a regular expression which will match a valid domain name without a subdomain?
...specs, your specs are wrong. g.co is a valid domain name but g is only one character.
– sch
Apr 24 '12 at 22:23
3
...
How do I use extern to share variables between source files?
...e protected against reinclusion, so that type
definitions (enum, struct or union types, or typedefs generally) do not
cause problems. The standard technique is to wrap the body of the
header in a header guard such as:
#ifndef FILE3B_H_INCLUDED
#define FILE3B_H_INCLUDED
...contents of header...
#e...
How to generate string of a certain length to insert into a file to meet a file size criteria?
...
You can always use the a constructor for string which takes a char and a number of times you want that character repeated:
string myString = new string('*', 5000);
This gives you a string of 5000 stars - tweak to your needs.
...
Remove secure warnings (_CRT_SECURE_NO_WARNINGS) from projects by default in Visual Studio
...n solution explorer.
Press Alt-F7 or right click in solution explorer and select "Properties"
Configurations:All Configurations
Click on the
Preprocessor Definitions line to invoke its editor
Choose
Edit...
Copy "_CRT_SECURE_NO_WARNINGS" into the Preprocessor Definitions white box on the top....