coding in c#

The computer is a machine for information processing. Unlike the factory in our comparison, for the computer, the raw material and the product are the same thing – information. In most cases, the input information is taken from any of the warehouses (files or RAM), to where it has been previously transported. Afterwards, it is processed by one or more processes and it comes out modified as a new product. Web based applications serve as a prime example. They use HTTP to transfer raw materials and products, and information processing usually has to do with extracting content from a database and preparing it for visualization in the form of HTML.
Managing the Computer
The whole process of manufacturing products in a factory has many levels of management. The separate machines and assembly lines have operators, the workshops have managers and the factory as a whole is run by general executives. Every one of them controls processes on a different level. The machine operators serve on the lowest level – they control the machines with buttons and levers. The next level is reserved for the workshop managers. And on the highest level, the general executives manage the different aspects of the manufacturing processes in the factory. They do that by issuing orders.
It is the same with computers and software – they have many levels of management and control. The lowest level is managed by the processor and its registries (this is accomplished by using machine programs at a low level) – we can compare it to controlling the machines in the workshops. The different responsibilities of the operating system (Windows 7 for example), like the file system, peripheral devices, users and communication protocols, are controlled at a higher level – we can compare it to the management of the different workshops and departments in the factory. At the highest level, we can find the application software. It runs a whole ensemble of processes, which require a huge amount of processor operations. This is the level of the general executives, who run the whole factory in order to maximize the utilization of the resources and to produce quality results.
Chapter 1. Introduction to Programming 71
The Essence of Programming
The essence of programming is to control the work of the computer on all levels. This is done with the help of "orders" and "commands" from the programmer, also known as programming instructions. To "program" means to organize the work of the computer through sequences of instructions. These commands (instructions) are given in written form and are implicitly followed by the computer (respectively by the operating system, the CPU and the peripheral devices).
To “program” means writing sequences of instructions in order to organize the work of the computer to perform something. These sequences of instructions are called “computer programs” or “scripts”.
A sequence of steps to achieve, complete some work or obtain some result is called an algorithm. This is how programming is related to algorithms. Programming involves describing what you want the computer to do by a sequence of steps, by algorithms.
Programmers are the people who create these instructions, which control computers. These instructions are called programs. Numerous programs exist, and they are created using different kinds of programming languages. Each language is oriented towards controlling the computer on a different level. There are languages oriented towards the machine level (the lowest) – Assembler for example. Others are most useful at the system level (interacting with the operating system), like C. There are also high level languages used to create application programs. Such languages include C#, Java, C++, PHP, Visual Basic, Python, Ruby, Perl, JavaScript and others.
In this book we will take a look at the C# programming language – a modern high level language. When a programmer uses C#, he gives commands in high level, like from the position of a general executive in a factory. The instructions given in the form of programs written in C# can access and control almost all computer resources directly or via the operating system. Before we learn how to write simple C# programs, let’s take a good look at the different stages of software development, because programming, despite being the most important stage, is not the only one.