In computer programming, a program is a set of instructions that tells a computer how to perform a certain task. For example, a word processing program allows users to create and edit documents. A web browser is also a program that instructs a computer to display, navigate, and interpret websites.
The process of creating a program can be very simple or complex. Regardless of the level of complexity, there are a few common components that define all programs.
First, a program is made up of variables and statements that represent information in a specific format. The variables contain numeric data, text, or images and the statements tell the program how to process these data. The variables and statements can be written in a programming language, which is a special type of computer language. The program can be compiled into machine code and then executed by the computer.
Second, a program is organized into modules that each have a defined function, which is a set of steps that the module must complete to return a result. The function is called the module’s base function and can be defined at the executable level or at the module level, depending on how it is structured.
Third, a program is organized into regions, which are logically separated sections of memory that each have their own virtual address space. These regions can be used to store program (text) pregions, data pregions, or stack pregions. The virtual address space is maintained by the kernel and varies with each operating system.
Fourth, a program is written in a specific language that has a defined syntax and semantics. These rules govern how the programmer should place declarations, expressions, and statements. They also determine what the output results are expected to be.
Fifth, a program is written in a language that is compiled into machine code and then executed by a computer. The compiler is a software tool that transforms the byte-level instructions into an assembly language. The assembly language is then run by the assembler, which translates the mnemonics into instruction numbers. The assembler is called the assembly language processor (APL).
Sixth, a program can be executed by an interactive user or by a batch program that does not require interaction. An interactive program can be started by a user or triggered by an event such as the receipt of a file. A batch program, on the other hand, runs, does its work, and then stops.
Seventh, a program can be implemented using a variety of tools and programming languages. Some of these include Visual Basic, Java, Python, and C++.
Eighth, a program can be developed in an interactive programming environment or through a command interpreter, such as the Microsoft command line interface (CLI). The syntax and semantics of a programming language depend on the platform on which the software is built.
Ninety-nine percent of the world’s computers are programmable. The technology is rapidly advancing, and the ability to program has become a valuable skill in many fields.