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dynamic_cast and static_cast in C++
...tual void DoIt() = 0; // pure virtual
virtual ~Base() {};
};
class Foo : public Base
{
public:
virtual void DoIt() { cout << "Foo"; };
void FooIt() { cout << "Fooing It..."; }
};
class Bar : public Base
{
public :
virtual void DoIt() { cout << "Bar"; }
voi...
What's the best way to inverse sort in scala?
...
Both sortWith and sortBy have a compact syntax:
case class Foo(time:Long, str:String)
val l = List(Foo(1, "hi"), Foo(2, "a"), Foo(3, "X"))
l.sortWith(_.time > _.time) // List(Foo(3,X), Foo(2,a), Foo(1,hi))
l.sortBy(- _.time) // List(Foo(3,X), Foo(2,a), Foo(1,hi))
l....
Remove all child elements of a DOM node in JavaScript
...ers may optimize for the case where the value is an empty string).
doFoo.onclick = () => {
const myNode = document.getElementById("foo");
myNode.innerHTML = '';
}
<div id='foo' style="height: 100px; width: 100px; border: 1px solid black;">
<span>Hello</span>
&l...
How to install gem from GitHub source?
...positories.
In your Gemfile:
# Use the http(s), ssh, or git protocol
gem 'foo', git: 'https://github.com/dideler/foo.git'
gem 'foo', git: 'git@github.com:dideler/foo.git'
gem 'foo', git: 'git://github.com/dideler/foo.git'
# Specify a tag, ref, or branch to use
gem 'foo', git: 'git@github.com:didel...
AngularJS : Differences among = & @ in directive scope? [duplicate]
...xplained ... if your directive looks like this:
<my-directive target="foo"/>
Then you have these possibilities for scope:
{ target : '=' }
This will bind scope.target (directive) to $scope.foo (outer scope). This is because = is for two-way binding and when you don't specify anything...
Difference between “and” and && in Ruby?
...ength, which can lead to peculiar behavior if you're not prepared for it:
foo = :foo
bar = nil
a = foo and bar
# => nil
a
# => :foo
a = foo && bar
# => nil
a
# => nil
a = (foo and bar)
# => nil
a
# => nil
(a = foo) && bar
# => nil
a
# => :foo
The same t...
Ruby regular expression using variable name
...n't work, does:
var = "Value"
str = "a test Value"
p str.gsub( /#{var}/, 'foo' ) # => "a test foo"
Things get more interesting if var can contain regular expression meta-characters. If it does and you want those matacharacters to do what they usually do in a regular expression, then the sam...
How to pass command line argument to gnuplot?
I want to use gnuplot to draw figure from data file, say foo.data . Currently, I hardcoded the data file name in the command file, say foo.plt , and run command gnuplot foo.plg to plot data. However, I want to pass the data file name as a command argument, e.g. running command gnuplot foo.plg f...
Command not found error in Bash variable assignment
...
You cannot have spaces around your '=' sign.
When you write:
STR = "foo"
bash tries to run a command named STR with 2 arguments (the strings '=' and 'foo')
When you write:
STR =foo
bash tries to run a command named STR with 1 argument (the string '=foo')
When you write:
STR= foo
bas...
What does T&& (double ampersand) mean in C++11?
...y implementations.
For example, a copy constructor might look like this:
foo(foo const& other)
{
this->length = other.length;
this->ptr = new int[other.length];
copy(other.ptr, other.ptr + other.length, this->ptr);
}
If this constructor was passed a temporary, the copy w...