“cannot resolve symbol” means that the Java compiler cannot locate a symbol referenced in your Java source code. The causes for this common error include: A missing class file A faulty CLASSPATH A symbol name is mispelled or miscapitalized A data type is incorrect, misspelled, or miscapitalized A method is called with the wrong number or types of arguments An undeclared variable cannot resolve symbol errors can be very difficult to track down. Code carefully!

In a singly (one-way) linear linked list, each node is divided into two parts. The first part contains the information of the element. The second part called the linked field or next pointer field contains the address of the next node in the list. A head pointer is used to hold the address of the first element in the list. Also, the last element of the linked list has a NULL value in the next pointer field to mark the end of the list. Declaration of a Linear Linked List Read More

Inheritance is what happens when a subclass receives variables or methods from a superclass. It is also when one class passes down its properties to another class. The main reason for inheritance is reusability. Distinguishing a new class from an existing class is called derivation. The old class is referred to as the base class and the new class is called a derived class or sub class. The derived class inherits some or all of the traits from the base class. A class can also inherit properties from more than Read More

A debugger is a type of software that allows a programmer to view every step a program takes in real-time. While a debugger will cause a program to run extremely slowly, it will allow a programmer to start and stop a program at any given time and modify the variables or actions that it takes while performing those actions. Debuggers allow programmers to prevent programs from performing undesired actions and are, as the name suggests, ideal for “debugging” a program. How Debuggers Work When a programmer runs a debugger, he/she Read More

The possibilities which may arise during deleting a node from a binary tree are as follows: Node is a terminal node: In this case, if the node is a left child of its parent, then the left pointer of its parent is set to NULL. Otherwise if the node is a right child of its parent, then the right pointer of its parent is set to NULL Node has only one child: In this case, the appropriate pointer of its parent is set to child node. Node has two children: Read More

Now that we have understood how to convert basic data types to class types and vice-versa, it is time to learn how to convert objects of one class type to another class type. The conversion between objects of different classes can be done using either a one-argument constructor or a conversion function. The choice depends upon whether the conversion routine has to be declared in the source class or in the destination class. To illustrate, consider a program that contains two classes: A and B. Also consider the statement: object_A Read More

JavaScript is a programming language and interactive web platform that allows users to interact with a webpage in a variety of different ways. For example, JavaScript can be used to create interactive drop-down navigation menus in a webpage, insert expandable content into forms or tables, and create interactive slideshows. JavaScript can also be used to create browser-based flash games and applications for a variety of platforms. How JavaScript Works JavaScript is a trademark of the Oracle Corporation and is similar to the programming language, “C”. JavaScript is designed to provide Read More

A breadth first search traversal method, visits all the successors of a visited node before visiting any successor of any of its child nodes. This is a contradiction to depth first traversal method; which visits the successor of a visited node before visiting any of its brothers, i.e., children of the same parent. A depth first traversal method tends to create very long, narrow trees; whereas breadth first traversal method tends to create very wide, short trees. Given an input graph G = (V, E) and source vertex s, from Read More

A graph is an important non linear data structure. This data structure is used to represent relationship between pairs of elements, which may not, necessarily, be hierarchical in nature. A graph is defined as: “Graph G is an ordered set (V, E), where V(G) represents the set of elements, called vertices, and E(G) represents the edges between these vertices.” Graphs can be of either type, Undirected Graph Directed Graph Figures below show sample graphs. V(G) = { v1, v2, v3, v4, v5 } E(G) = { e1, e2, e3, e4, Read More

SDLC (Systems Development Life Cycle) is the process of creating or modifying existing systems and the models and methodologies that are used in the process. In the fields of software engineering and information systems, SDLC denotes a framework of methodologies aimed at the creation of an information/software system, i.e. the software development process. SDLC covers many activities across well defined phases. These include questioning why the information system needs to be built, to charting feasibility factors, analyzing issues that are expected to crop up, zeroing in on a certain design Read More