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What is the point of function pointers?
...ss functor {
public:
functor(const std::string& prompt) : prompt_(prompt) {}
void operator()(int i) {std::cout << prompt_ << i << '\n';}
private:
std::string prompt_;
};
functor f("the answer is: ");
f(42);
Another advantage is that it is sometimes easier ...
How to record webcam and audio using webRTC and a server-based Peer connection
...mediaOptions.audio;
navigator.mediaDevices.getUserMedia(media.gUM).then(_stream => {
stream = _stream;
id('gUMArea').style.display = 'none';
id('btns').style.display = 'inherit';
start.removeAttribute('disabled');
recorder = new MediaRecorder(stream);
recorder.ond...
Escape a string for a sed replace pattern
...es, forward slash for end of statement and & for replace all):
ESCAPED_REPLACE=$(printf '%s\n' "$REPLACE" | sed -e 's/[\/&]/\\&/g')
# Now you can use ESCAPED_REPLACE in the original sed statement
sed "s/KEYWORD/$ESCAPED_REPLACE/g"
If you ever need to escape the KEYWORD string, the fol...
Is there a HTML opposite to ?
...ipt" charset="utf-8">
$(document).ready(function() {
$.get('_test.html', function(html) {
$('p:first').after(html);
});
});
</script>
</head>
<body>
<p>This is content at the top of the page.</p>
<p>This is content at th...
What is the difference between `sorted(list)` vs `list.sort()`?
...ably faster as it is written in C:
def sorted(iterable, key=None):
new_list = list(iterable) # make a new list
new_list.sort(key=key) # sort it
return new_list # return it
when to use which?
Use list.sort when you do not wish to retain the original sort ord...
Generating an MD5 checksum of a file
...y and feed them to the md5 method:
import hashlib
def md5(fname):
hash_md5 = hashlib.md5()
with open(fname, "rb") as f:
for chunk in iter(lambda: f.read(4096), b""):
hash_md5.update(chunk)
return hash_md5.hexdigest()
Note: hash_md5.hexdigest() will return the hex s...
Is the size of C “int” 2 bytes or 4 bytes?
... size for the preproccesor, you can check the predefined macros such as INT_MAX. If the value is not the one expected by your code, then the byte size of int is different on the current compiler/platform combination.
– Walt Sellers
Apr 15 '14 at 17:10
...
Can not connect to local PostgreSQL
... the permissions on the socket file and its directories /var and /var/pgsql_socket. Your Rails app (OSX user) must have execute (x) permissions on these directories (preferably grant everyone permissions) and the socket should have full permissions (wrx). You can use ls -lAd <file> to check t...
Signed to unsigned conversion in C - is it always safe?
...hort Answer
Your i will be converted to an unsigned integer by adding UINT_MAX + 1, then the addition will be carried out with the unsigned values, resulting in a large result (depending on the values of u and i).
Long Answer
According to the C99 Standard:
6.3.1.8 Usual arithmetic conversions...
How to dismiss keyboard for UITextView with return key?
...n Xcode 6.4 , Swift 2.0. I set the key using IB.
– MB_iOSDeveloper
Jul 9 '15 at 7:20
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