Pinnacle Technology Interview Questions and Answers

Design patterns are used to solve common software design problems. Each use case requires a specific pattern.

• Design patterns are reusable solutions to common software design problems.

• Each use case requires a specific pattern to be used.

• Examples of design patterns include Singleton, Factory, and Observer.

• The choice of pattern depends on the problem being solved and the requirements of the system.

A delegate is a type that represents references to methods with a specific parameter list and return type.

• Delegates are similar to function pointers in C++ or pointers to member functions in C++.

• Delegates are used to pass methods as arguments to other methods.

• Delegates can be used to define callback methods.

• Syntax: delegate return_type delegate_name(parameter_list);

An event is an occurrence or happening that can be detected and responded to by software.

• Events can be user actions (clicking a button, typing in a text box)

• Events can be system-generated (timer expiration, network packet arrival)

• Events are typically handled by event handlers or listeners in software development

WPF C# is a framework for building desktop applications. Binding is a way to connect UI elements to data sources.

• WPF stands for Windows Presentation Foundation

• C# is the programming language used for WPF development

• Binding allows for automatic updates of UI elements when data changes

• Example code for binding:

• DataContext is used to set the data source for binding

Use synchronized block or double-checked locking to ensure only one thread can access singleton instance at a time.

• Use synchronized block to ensure thread safety in getInstance() method

• Implement double-checked locking to minimize synchronization overhead

• Consider using Enum singleton for thread safety without synchronization

Singleton pattern ensures a class has only one instance and provides a global point of access to it.

• Create a private static instance variable of the class

• Make the constructor private to prevent instantiation from outside the class

• Provide a static method to access the instance, creating it if necessary