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Is there a way to instantiate objects from a string holding their class name?
...<DerivedA>;
map["DerivedB"] = &createInstance<DerivedB>;
And then you can do
return map[some_string]();
Getting a new instance. Another idea is to have the types register themself:
// in base.hpp:
template<typename T> Base * createT() { return new T; }
struct BaseFactor...
String was not recognized as a valid DateTime “ format dd/MM/yyyy”
I am trying to convert my string formatted value to date type with format dd/MM/yyyy .
13 Answers
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Why can't I make a vector of references?
... not assignable (you can only initialize them once when they are declared, and you cannot make them reference something else later). Other non-assignable types are also not allowed as components of containers, e.g. vector<const int> is not allowed.
...
Why doesn't RecyclerView have onItemClickListener()?
I was exploring RecyclerView and I was surprised to see that RecyclerView does not have onItemClickListener() .
32 Ans...
COALESCE Function in TSQL
...f same datatype or must be of matching-types (that can be "implicitly auto-converted" into a compatible datatype), see examples below:
PRINT COALESCE(NULL, ('str-'+'1'), 'x') --returns 'str-1, works as all args (excluding NULLs) are of same VARCHAR type.
--PRINT COALESCE(NULL, 'text', '3', 3) -...
PHP Sort a multidimensional array by element containing date
...
This should work. I converted the date to unix time via strtotime.
foreach ($originalArray as $key => $part) {
$sort[$key] = strtotime($part['datetime']);
}
array_multisort($sort, SORT_DESC, $originalArray);
One-liner versio...
Read/write files within a Linux kernel module
...thin Linux kernel when possible. The main idea is to go "one level deeper" and call VFS level functions instead of the syscall handler directly:
Includes:
#include <linux/fs.h>
#include <asm/segment.h>
#include <asm/uaccess.h>
#include <linux/buffer_head.h>
Opening a file...
Calendar date to yyyy-MM-dd format in java
How to convert calendar date to yyyy-MM-dd format.
9 Answers
9
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Performance optimization strategies of last resort [closed]
...tors of floats. Changing the code to carry around the extra empty slot and converting the calculation to floating point from fixed point allowed for a slightly less-accurate but much faster result.
– RBerteig
May 30 '09 at 2:19
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What is the difference between localStorage, sessionStorage, session and cookies?
...ocalStorage only allow you to store strings - it is possible to implicitly convert primitive values when setting (these will need to be converted back to use them as their type after reading) but not Objects or Arrays (it is possible to JSON serialise them to store them using the APIs). Session stor...