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What's the difference between passing by reference vs. passing by value?
...to it, I'll change the caller's variable itself, not e.g. whatever it is pointing to if it's a pointer.
This is now considered bad practice (as an implicit dependency). As such, virtually all newer languages are exclusively, or almost exclusively pass-by-value. Pass-by-reference is now chiefly use...
Can a recursive function be inline?
...
First, the inline specification on a function is just a hint. The compiler can (and often does) completely ignore the presence or absence of an inline qualifier. With that said, a compiler can inline a recursive function, much as it can unroll an infinite loop. It simply has to ...
Deleting elements from std::set while iterating
...get to the temp. For example, re-write your loop as follows:
std::set<int>::iterator it = numbers.begin();
std::set<int>::iterator tmp;
// iterate through the set and erase all even numbers ...
Cannot use ref or out parameter in lambda expressions
... can be accessed after the method frame is no longer on the stack
Func<int> Example(int p1) {
return () => p1;
}
Another property of captured variables is that changes to the variable are also visible outside the lambda expression. For example the following prints 42
void Example2(in...
Can table columns with a Foreign Key be NULL?
...
Yes, you can enforce the constraint only when the value is not NULL. This can be easily tested with the following example:
CREATE DATABASE t;
USE t;
CREATE TABLE parent (id INT NOT NULL,
PRIMARY KEY (id)
) ENGINE=INNODB;
CREATE TABLE...
nvarchar(max) vs NText
...
Wanted to add my experience with converting. I had many text fields in ancient Linq2SQL code. This was to allow text columns present in indexes to be rebuilt ONLINE.
First I've known about the benefits for years, but always assumed that converting would mea...
Round to 5 (or other number) in Python
...thon, but this works for me:
Python 2
def myround(x, base=5):
return int(base * round(float(x)/base))
Python3
def myround(x, base=5):
return base * round(x/base)
It is easy to see why the above works. You want to make sure that your number divided by 5 is an integer, correctly rounde...
What is the best way to find the users home directory in Java?
...\Application Data (CSIDL_LOCAL_APPDATA).
Sample JNA code:
public class PrintAppDataDir {
public static void main(String[] args) {
if (com.sun.jna.Platform.isWindows()) {
HWND hwndOwner = null;
int nFolder = Shell32.CSIDL_LOCAL_APPDATA;
HANDLE hToken...
Java: method to get position of a match in a String?
...
The family of methods that does this are:
int indexOf(String str)
indexOf(String str, int fromIndex)
int lastIndexOf(String str)
lastIndexOf(String str, int fromIndex)
Returns the index within this string of the first (or last) occurrence of the specified ...
iPhone OS: How do I create an NSDate for a specific date?
...is basic stuff.
Anyway, here's the helper class I used in my project, to convert a string into an NSDate value :
@implementation DateHelper
+(NSDate*)parseDateString:(NSString *)dateString
{
NSDateFormatter *rfc3339TimestampFormatterWithTimeZone = [[NSDateFormatter alloc] init];
[rfc3339...