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Uses for Optional
...
The main point of Optional is to provide a means for a function returning a value to indicate the absence of a return value. See this discussion. This allows the caller to continue a chain of fluent method calls.
This most closely matc...
Pros and cons of AppSettings vs applicationSettings (.NET app.config / Web.config)
... wanted to configure there really is a number - someone could put a string into that setting..... you just access it as ConfigurationManager["(key)"] and then it's up to you to know what you're dealing with.
Also, over time, the <appSettings> can get rather convoluted and messy, if lots of p...
How to filter SQL results in a has-many-through relation
...re-knowledge which clubs will be queried):
ALTER TABLE student ADD CONSTRAINT student_pkey PRIMARY KEY(stud_id );
ALTER TABLE student_club ADD CONSTRAINT sc_pkey PRIMARY KEY(stud_id, club_id);
ALTER TABLE club ADD CONSTRAINT club_pkey PRIMARY KEY(club_id );
CREATE INDEX sc_club_id_idx ON stud...
What is the difference between Serializable and Externalizable in Java?
... performance problem. To handle this situation, the java.io.Externalizable interface was provided, which is like java.io.Serializable but with custom-written mechanisms to perform the marshalling and unmarshalling functions (you need to implement readExternal and writeExternal methods on your class)...
When to use Preorder, Postorder, and Inorder Binary Search Tree Traversal strategies
...s an inherent sequence in the nodes, and you want to flatten the tree back into its original sequence, than an in-order traversal should be used. The tree would be flattened in the same way it was created. A pre-order or post-order traversal might not unwind the tree back into the sequence which w...
When should I use malloc in C and when don't I?
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char *some_memory = "Hello World";
is creating a pointer to a string constant. That means the string "Hello World" will be somewhere in the read-only part of the memory and you just have a pointer to it. You can use the string as read-only. You cannot make changes to it. Exam...
Qt events and signal/slots
...ass (have a look at your moc_classname.cpp file for more), but most of the interclass communication that you will produce will probably use signals and slots. Signals can get delivered immediately or deferred via a queue (if you are using threads).
A signal can be generated.
...
Why is the .bss segment required?
...he "copy-down" can be run sequentially, hence faster. If it were not split into the two segments then the initialisation would have to skip the RAM spots belonging to the uninitialised variables, so wasting time.
– CL22
May 15 '13 at 16:29
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Do fragments really need an empty constructor?
...guments (bundle)
For example:
public static final MyFragment newInstance(int title, String message) {
MyFragment f = new MyFragment();
Bundle bdl = new Bundle(2);
bdl.putInt(EXTRA_TITLE, title);
bdl.putString(EXTRA_MESSAGE, message);
f.setArguments(bdl);
return f;
}
And o...
Why must jUnit's fixtureSetup be static?
... @BeforeClass
public static void beforeClass() {
System.out.println("beforeClass");
}
@AfterClass
public static void afterClass() {
System.out.println("afterClass");
}
@Before
public void before() {
System.out.println(this + "\tbefore");
}
...