Design and implementation

Main articles: Software development, Computer programming, and Software engineering
Design and implementation of a software varies depending on the complexity of the software. For instance design and creation of Microsoft Word software will take much longer time than designing and developing Microsoft Notepad because of the difference in functionalities in each one.
Software is usually designed and created (coded/written/programmed) in integrated development environments (IDE) like emacs, xemacs, Microsoft Visual Studio and Eclipse that can simplify the process and compile the program. As noted in different section, software is usually created on top of an existing software and the application programming interface (API) that the underlying software provides like GTK+, JavaBeans, Swing etc. Libraries (APIs) are categorized for different purposes. For instance JavaBeans library is used for designing enterprise applications, Windows Forms library is used for designing graphical user interface (GUI) applications like Microsoft Word and Windows Communication Foundation is used for designing web services. There are also underlying concepts in computer programming like quicksort, hashtable, array, binary tree that can be useful to creating a software. When a program is designed, it relies on the API. For instance, if a user is designing a Microsoft Windows desktop application, he/she might use the .NET Windows Forms library to design the desktop application and call its APIs like Form1.Close()