new-operator

In my recent posts about using or omitting a "new" keyword in Scala ( "new" keyword in Scala ) I was told that the omission comes from the fact that certain classes have companion objects defined with apply method on them. My question is: are we able to tell or is there any general rule to distinguish which classes/objects have a companion object and apply method? Thanks in advance and sorry of it's a stupid question, but coming from a Java background it is a bit confusing. In the Scala API documentation , you see a little icon in the list on the left side. If you click on that, you go to the

I come from a c++ background and I find myself constantly doing this in java: SomeClass sc=new SomeClass(); if(null!=sc) { sc.doSomething(); } What I want to know is what will be in the variable sc if the constructor fails for some reason (like maybe not enough memory). I can' t find a straight answer, and I am worried that I am just wasting my time because maybe if the new operator fails would the program just crash anyway? polygenelubricants The Java Specification Language 3rd Edition covers your question thoroughly: 12.5 Creation of New Class Instances Whenever a new class instance is

I have a attribute called: description and I want to have the following in it with new lines: This is the content description section. Download instruction: This is the contents on how to download contents. Hotline support: This is the hotline for contents. How do I create a new line for it in xml? Basically you want to insert CRLF: CR code: LF code: <myelement description="line1 line2 line3"/> If you need it in XML attribute , you'll have to use character entities: <element attribute="First line Second line Third line..." /> Try it like this: <description><![CDATA[first line<br />second

Today, I found something in legacy code. It has "static new" for one function. It looks like this. class Foo { public static void Do() { Console.WriteLine("Foo.Do"); } } class Bar: Foo { public static new void Do() { Console.WriteLine("Bar.Do"); } } I don't understand the static new modifier for the Do method in class Bar . In C#, static method can only be invoked with class name instead of object name. So, I don't think there is any difference between having the "new" and not. Generally, if some syntax is unnecessary, C# just treat it is error. Anybody has any idea about why C# allows such

In the code below I receive the compile error Error Too many arguments to 'Public Sub New()' on the Dim TestChild As ChildClass = New ChildClass("c") . I do not receive it on TestChild.Method1() even though they are both on the base class I am inheriting from. Public Class BaseClass Public ReadOnly Text As String Public Sub New(ByVal SetText As String) Text = SetText End Sub Public Sub New() Text = "" End Sub End Class Public Class ChildClass Inherits BaseClass End Class Public Class TestClass Sub Test() Dim TestChild As ChildClass = New ChildClass("c") TestChild.Method1() End Sub End Class I

I reviewed the answers provided to the "GUI Programming APIs" post and wondering if these answers still apply. https://stackoverflow.com/questions/610/gui-programming-apis Specifically from that thread it appears that QT is the one that was most referenced with wxWidgets and Shoes a close second and third. I just wanted to make sure that a definitive winner has not emerged in the past 6 months since that question was posted. I am constrained to target OpenSource and Freeware solutions, so I will strongly lean that way. Thanks for any feedback and insights. I've got a little experience with

This question already has an answer here: Why doesn't delete set the pointer to NULL? 12 answers Why doesn't free(p) set p to NULL? 9 answers I have small piece of code: #include <iostream> using namespace std; int main() { int *p = new int(10); if(p != NULL) { cout<<"Deleted dynamic allocated memory"<<endl; delete p; } if(p == NULL) { cout<<"NULL"<<endl; } else { cout<<"Not NULL"<<endl; } return 0; } After deleting dynamic allocated memory using delete operator, Why compilers do not assigned NULL to pointer(like p = NULL) automatically? It would often be unnecessary, particularly in well

Since I started learning C++, I have always read that the 'new' operator calls the constructor of the object before returning the pointer to the allocated memory. So, out of curiosity I checked the source code for 'new' and I found the following at http://gcc.gnu.org/viewcvs/gcc/trunk/libstdc%2B%2B-v3/libsupc%2B%2B/new_op.cc?revision=197380&view=markup _GLIBCXX_WEAK_DEFINITION void * operator new (std::size_t sz) _GLIBCXX_THROW (std::bad_alloc) { void *p; /* malloc (0) is unpredictable; avoid it. */ if (sz == 0) sz = 1; p = (void *) malloc (sz); while (p == 0) { new_handler handler = std::get