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Is there a standard sign function (signum, sgn) in C/C++?
...T val) {
return (T(0) < val) - (val < T(0));
}
Benefits:
Actually implements signum (-1, 0, or 1). Implementations here using copysign only return -1 or 1, which is not signum. Also, some implementations here are returning a float (or T) rather than an int, which seems wasteful.
Works ...
Flask raises TemplateNotFound error even though template file exists
....py
templates/
home.html
myproject/
mypackage/
__init__.py
templates/
home.html
Alternatively, if you named your templates folder something other than templates and don't want to rename it to the default, you can tell Flask to use that other director...
Why define an anonymous function and pass it jQuery as the argument?
...de demo code from the backbone.js screencasts. In it, the backbone code is all enclosed in an anonymous function that is passed the jQuery object:
...
What differences, if any, between C++03 and C++11 can be detected at run-time?
...onstrate breaking changes. The following is a tweaked testcase, which initially was used to demonstrate such a change, but now is used to test for C++0x or C++03.
struct X { };
struct Y { X x1, x2; };
struct A { static X B(int); };
typedef A B;
struct C : A {
using ::B::B; // (inheriting const...
How can I convert a Unix timestamp to DateTime and vice versa?
...
docs.microsoft.com/en-us/dotnet/api/…
– yedevtxt
Jul 12 '17 at 16:35
This...
What is the difference between a symbolic link and a hard link?
... (Or is it multiple inodes? Not sure.)
A file in the file system is basically a link to an inode.
A hard link, then, just creates another file with a link to the same underlying inode.
When you delete a file, it removes one link to the underlying inode. The inode is only deleted (or deletable/ove...
adding noise to a signal in python
...umpy as np
import matplotlib.pyplot as plt
t = np.linspace(1, 100, 1000)
x_volts = 10*np.sin(t/(2*np.pi))
plt.subplot(3,1,1)
plt.plot(t, x_volts)
plt.title('Signal')
plt.ylabel('Voltage (V)')
plt.xlabel('Time (s)')
plt.show()
x_watts = x_volts ** 2
plt.subplot(3,1,2)
plt.plot(t, x_watts)
plt.title...
How do I make HttpURLConnection use a proxy?
... don't need to repeat yourself (DRY)
http://docs.oracle.com/javase/7/docs/api/java/net/doc-files/net-properties.html#Proxies
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How to encrypt/decrypt data in php?
...er generator. The following example would be recommended (>= 5.3):
$key_size = 32; // 256 bits
$encryption_key = openssl_random_pseudo_bytes($key_size, $strong);
// $strong will be true if the key is crypto safe
This can be done once or multiple times (if you wish to create a chain of encrypti...
Unable to find specific subclass of NSManagedObject
...://stackoverflow.com/a/31287260/1187415).
Remark: This answer was originally written for Xcode 6.
There were some changes in the various Xcode 7 beta releases with
respect to this problem. Since it is an accepted answer with many
upvotes and links to it, I have tried to summarize the situation
fo...