Programming, Data Structures & Algorithms

Just follow the program to find Palindrome  in java: import java.io.BufferedReader; import java.io.InputStreamReader; public class Palindrome {     public static void main(String[] args) throws Exception {    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));      String s1 = new String();          s1 =br.readLine();          s1 = s1.toLowerCase();     String s2 = new StringBuffer(s1).reverse().toString();          if(s1.equals(s2)){         System.out.println("Palindrome");     }else          System.out.println("Not Palindrome");      } }

 BufferedReader use to read text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.The buffer size may be specified, or the default size may be used. The default is large enough for most purposes. In Java  BufferedReader is a efficient method to read an input. Here given a short example to read a string from user and print it: package palindrome; import java.io.BufferedReader; import java.io.InputStreamReader; public class  inputExample   {     public static void main(String[] args) throws Exception {    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));     String s = new String();       s =br.readLine();     System.out.println(s);     } }

BufferedReader Read text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines. The buffer size may be specified, or the default size may be used. The default is large enough for most purposes. Where Scanner is a simple text scanner which can parse primitive types and strings using regular expressions. A Scanner breaks its input into tokens using a delimiter pattern, which by default matches whitespace. The resulting tokens may then be converted into values of different types using the various next methods. Scanner is used for parsing tokens from the contents of the stream while BufferedReader just reads the stream and does not do any special parsing. In currently latest JDK6 release/build, the Scanner has a littler buffer (1KB char buffer) as opposed to the BufferedReader (8KB byte buffer), but it's more than enough.As to the choice, use the Scanner if you want to parse the file, use th...

Each language has its own lexicon of terms with special meaning. In C Programming Language, the word Function means a program routine. In Java, the term Function does not have any special meaning. Whereas Method means one of the routines that forms the implementation of a class. First let we know what is Function? A function is a piece of reuseable code that is called by name. In C or C++ we used to say function to a reusable code. It can be passed data to operate on (arguments / parameters) and can optionally return a result. Function is a portion of code within a larger program, which performs a specific task and is relatively independent of the remaining code. So What is Method?? A method  is a piece of code that is called by name that is associated with an object. A method is almost identical to a function but it's purpose is generally to operate on the data contained within the component (class). Method is a function that is a member of a class. ...

Polymorphism, Encapsulation, and Inheritance Work Together: When properly applied, polymorphism, encapsulation, and inheritance combine to produce a programming environment that supports the development of far more robust and scaleable programs than does the process-oriented model. A well-designed hierarchy of classes is the basis for reusing the code in which you have invested time and effort developing and testing. Encapsulation allows you to migrate your implementations over time without breaking the code that depends on the public interface of your classes. Polymorphism allows you to create clean, sensible, readable, and resilient code. Of the two real-world examples, the automobile more completely illustrates the power of object-oriented design. Dogs are fun to think about from an inheritance standpoint, but cars are more like programs. All drivers rely on inheritance to drive different types (subclasses) of vehicles. Whether the vehicle is a school bus, a Mercedes sedan, a...

Polymorphism In JAV A Programming Language: Polymorphism (from the Greek, meaning “many forms”) is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of the situation. Consider a stack (which is a last-in, first-out list). You might have a program that requires three types of stacks. One stack is used for integer values, one for floating-point values, and one for characters. The algorithm that implements each stack is the same, even though the data being stored differs. In a non– object-oriented language, you would be required to create three different sets of stack routines, with each set using different names. However, because of polymorphism, in Java you can specify a general set of stack routines that all share the same names. More generally, the concept of polymorphism is often expressed by the phrase “one interface, multiple methods.” This means that it is possible to design a generic inter...

Inheritance in JAVA Programming Language: Inheritance is the process by which one object acquires the properties of another object. This is important because it supports the concept of hierarchical classification. As mentioned earlier, most knowledge is made manageable by hierarchical (that is, top-down) classifications. For example, a Golden Retriever is part of the classification dog, which in turn is part of the mammal class, which is under the larger class animal. Without the use of hierarchies, each object would need to define all of its characteristics explicitly. However, by use of inheritance, an object need only define those qualities that make it unique within its class. It can inherit its general attributes from its parent. Thus, it is the inheritance mechanism that makes it possible for one object to be a specific instance of a more general case. Let’s take a closer look at this process. Most people naturally view the world as made up of objects that are re...

Encapsulation: Encapsulation is the mechanism that binds together code and the data it manipulates, and keeps both safe from outside interference and misuse. One way to think about encapsulation is as a protective wrapper that prevents the code and data from being arbitrarily accessed by other code defined outside the wrapper. Access to the code and data inside the wrapper is tightly controlled through a well-defined interface. To relate this to the real world, consider the automatic transmission on an automobile. It encapsulates hundreds of bits of information about your engine, such as how much you are accelerating, the pitch of the surface you are on, and the position of the shift lever. You, as the user, have only one method of affecting this complex encapsulation: by moving the gear-shift lever. You can’t affect the transmission by using the turn signal or windshield wipers, for example. Thus, the gear-shift lever is a well-defined (indeed, unique) interface to the transm...

Abstraction in JAVA Programming Language: An essential element of object-oriented programming is abstraction. Humans manage complexity through abstraction. For example, people do not think of a car as a set of tens of thousands of individual parts. They think of it as a well-defined object with its own unique behavior. This abstraction allows people to use a car to drive to the grocery store without being overwhelmed by the complexity of the parts that form the car. They can ignore the details of how the engine, transmission, and braking systems work. Instead they are free to utilize the object as a whole. A powerful way to manage abstraction is through the use of hierarchical classifications. This allows you to layer the semantics of complex systems, breaking them into more manageable pieces. From the outside, the car is a single object. Once inside, you see that the car consists of several subsystems: steering, brakes, sound system, seat belts, heating, cellular phone, and...

  Object-Oriented Programming and:   Object-oriented programming (OOP) is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction, encapsulation, messaging, modularity, olymorphism, and inheritance. Many modern programming languages now support OOP, at least as an option. JAVA Programming Language: Object-oriented programming is at the core of Java. In fact, all Java programs are object-oriented, this isn’t an option the way that it is in C++, for example. OOP is so integral to Java that you must understand its basic principles before you can write even simple Java programs. Therefore, this chapter begins with a discussion of the theoretical aspects of OOP.