Java Programming

A base class constructor is simply a constructor that is declared within a base class. There is nothing particularly special about them since all constructors are only of relevence and applicable to the classes in which they are declared.

That depends on the type of file and what you mean by "empty". Generally, fopen() called on an existing file, with the "w" option instead of the "a" option will truncate the file to zero length. To delete a file completely is a different process. Function truncate is your friend.

Best way to learn Java is start from basic.Get a clear picture about JVM and JRE.Even if you write a simple program,try to understand what happens behind your code.I suggest you to read more about java at http://allinalljava.blogspot.com. At first while writing your code attach java source behind ,due to that you can easily admire real scenario happen in it.

I suggest you try http://academicjava.com. It's a resource of many example programs with explanations and there's a very good tutorial.

"Head first JAVA" is the book I recommend but it's a question of what's best for you. Go to a good bookshop and browse what's available.

At first, i would like to tell you the BEST way to learn JAVA is just "Type Java programs n execute them". start with simple programs...

"Head first JAVA" - It is the one of the best book to learn Java.

If you want to understand Java's advantages elaborately , then u can refer this page too

http://www.artima.com/insidejvm/ed2/

Best way to learn java is think of something real-world that you understand well and can automate. Write something like an electronic recipe organizer. The best book? Do a google search for "Java, The Complete Reference, J2se" Good luck!

That is a good book. Also try "Java In A Nutshell" from O'Reiley books. It makes an excellent quick reference and is very straightforward.

Yes, these are great resources and adding one more resource to the list which i found helpful while starting with Java --> the tutorials from Sun. You can find them here http://java.sun.com/docs/books/tutorial/

Happy Learning : )

an IOException is any unexpected problem the compiler encounters while attempting to run a program. Possible problems the compiler may encounter are attempting to read from a file that does not exist, write to a file which has an invalid name (a slash or a question mark in the title should do it), or attempting to read the next token in a file when there are no more tokens.

If you are getting this error message, it means you are trying to use a class that is not located in your JVM classpath. In order to resolve this error, you must find the .class or the .jar file that contains the class you need, and add it to your classpath.

Depending on the application, it might be as simple as changing your CLASSPATH environment variable. Here is a good article on the Java classpath:

http://en.wikipedia.org/wiki/Classpath_(Java)

Here is a good online utility to help you quickly find the right jar and download it. It will save you hours of searching through various blog posts on the internet trying to find out which jar contains which class file!

http://www.ClassNotFound.com/

IN C++

#include <iostream> int main(int argc, char *argv[]) { using namespace std; cout << "There are " << argc << " arguments:" << endl; // Loop through each argument and print its number and value for (int nArg=0; nArg < argc; nArg++) cout << nArg << " " << argv[nArg] << endl; return 0; }

It means that it is by itself - as opposed to being bundled with other applications for example.

The easiest way is to use a prime sieve (google Sieve of Eratosthenes).

Here is pseudo-code for the algorithm.

- create a boolean array of size n

- for every true index 2 through n

- - keep the index as true, mark all multiples of the index as false.

So, for example, if n=10

start with 2, keep 2 true. Mark 4,6,8,10 as false.

next is 3, keep it true. mark 6,9 as false (6 was already false).

next is 4, it is false, skip it.

next is 5, keep it true. mark 10 as false (it was already false).

6 is false, skip it

7 is true, keep it true. the next multiple of 7 is greater than 10

8,9, 10 are all false.

you are done - the values marked true (1,2, 3,5,7) are your primes.

There are only two types of inheritance in object oriented programming:

Single inheritance: where a class inherits directly from just one base class.

Multiple inheritance: where a class inherits directly from two or more base classes.

Multi-level inheritance is often thought of as being a separate type of inheritance, however inheritance relates to a derived class and those that it directly inherits from. If a base class is itself a derived class (an intermediate class), then its base class or classes are simply indirect base classes of the derivative. But in isolation, the intermediate class either uses single or multiple inheritance, even if its base class or classes are also intermediates.

Virtual inheritance is also thought of as being a separate type, however virtual inheritance doesn't change the relationship between classes within the hierarchy. the only difference virtual inheritance makes is that the virtual base class or classes are constructed by the most-derived class within the current hierarchy, rather than by their most direct descendants. In this way, only one instance of each virtual base exists in the hierarchy, rather than multiple instance as would normally exist. The actual inheritance is still single or multiple, however.

The computer-programming language Java is used when a powerful object-oriented programming language that can execute on a variety of operating systems, with little or no alterations to the code, is needed. Java "applets" are ideal for distribution over the internet owing to the diversity of systems that support Java and the inherently small size of the applet download.

Substring method creates smaller string form bigger string , every time a new string is created but original character array buffer is used. so even if original string is 1G in size and substring is just 1K memory held by substring is 1G because of backed array. this can cause memory leak and prevent original string from garbage collection even if there is no direct reference.

The finally clause is used to provide the capability to execute code no matter whether or not an exception is thrown or caught. It is usually used in places where we are connecting to a database so that, we can close the connection or perform any cleanup even if the query execution in the try block caused an exception

For the most part Javascript is used to make web pages dynamic, move elements on the page, highlighting areas of the page, bringing in new content from the server, etc. There are other cases though like node.js where it's used as a server to make the web pages themselves. There are also a few cases outside of the web world where javascript can be used, some robotics, etc.

Declaring an inner class static means that class only has access to the "outer" class public and private static fields. A non-static inner class has access to the outer class's instance data. Top-level classes cannot be declared static.

The advantage of a static inner class is that it doesn't need an instance of the containing class to work and it's bytecode class size is smaller for that reason - less overhead.

The size of a byte primitive is 8-bits.

Java is a programming language that allows users to play games, chat with other users, and perform financial calculations among other things. The online site "Oracle" is excellent for downloading all Java software, including Java JDK.

when the object is instantiated(created) and delared,it has to assigned with variables.constructor is used for this purpose. syntax: classname ojbectname=new classname(); here classname() is a constructor. eg: box bb=new box(5,10); when this object is instantiated,it can be directly accessed by the constructor(similar to method but without a void because the instance variables are directly used) box(5,10) { }

The C++ string classes are derived from the std::basic_string<T> template class, where T is a character type. The standard provides the two most common string types, std::string (std::basic_string<char>) and std::wstring (std::basic_string<wchar_t>). The former is used for ASCII strings (which includes UTF-8 strings) while the latter is used for wide-character strings, particularly UNICODE strings.

All standard library strings are represented by an array of some character type (such as char or wchar_t) however, unlike an ordinary array, the individual character elements cannot be re-ordered other by overwriting each character. If you simply need an array of characters that can be re-ordered then use a std::vector<char> or std::vector<wchar_t> rather than a string.

The standard library strings include a rich set of methods, operations and algorithms that are commonly used with strings, such as std::string::find() to locate a character within a string, std::string::substr() to extract a substring from a string, and operator+= to concatenate one string onto another. Most implementations include the short string optimisation so that short strings (up to around 14 characters or so) may be stored in local memory rather than on the heap. Many strings tend to be short so this can provide enormous performance benefits with little cost in terms of memory.