It is also possible for some components of a piece of software to be written and compiled separately, in an arbitrary programming language, and later integrated into the software using a technique called library linking. For example, a program written primarily in the C programming language, might have portions written in assembly language for optimization purposes.
Though the practice is uncommon, a program's source code can be written in different programming languages.
The source code for a particular piece of software may be contained in a single file or many files. With prologue comments indicated in red, inline comments indicated in green, and program statements indicated in blue. Written in object-oriented programming style, it demonstrates boilerplate code. Source code can also be stored in a database (as is common for stored procedures) or elsewhere.Ī more complex Java source code example. The source code which constitutes a program is usually held in one or more text files stored on a computer's hard disk usually, these files are carefully arranged into a directory tree, known as a source tree.
B: TeX, The Program by Donald Knuth, PGP Source Code and Internals by Philip Zimmermann, PC SpeedScript by Randy Thompson, and ♜/OS, The Real-Time Kernel by Jean Labrosse.
Occasionally the entire source code to a large program is published as a hardback book, such as Computers and Typesetting, vol. Most early computer magazines published source code as type-in programs. For decades, IBM distributed source code with its software product licenses, until 1983. At that time, the cost of developing and supporting software was included in the price of the hardware. When IBM first offered software to work with its machine, the source code was provided at no additional charge.
This first-generation programming language had no distinction between source code and machine code. The earliest programs for stored-program computers were entered in binary through the front panel switches of the computer. While some, like the FSF, argue that an intermediate file "is not real source code and does not count as source code", others find it convenient to refer to each intermediate file as the source code for the next steps. Often there are several steps of program translation or minification between the original source code typed by a human and an executable program. It is therefore so construed as to include machine code, very high level languages and executable graphical representations of systems. An example from an article presented on the annual IEEE conference and on Source Code Analysis and Manipulation: įor the purpose of clarity "source code" is taken to mean any fully executable description of a software system. The notion of source code may also be taken more broadly, to include machine code and notations in graphical languages, neither of which are textual in nature. Source code (also referred to as source or code) is the version of software as it is originally written (i.e., typed into a computer) by a human in plain text (i.e., human readable alphanumeric characters). The Linux Information Project defines source code as: This first known " Hello world" snippet from the seminal book The C Programming Language originates from Brian Kernighan in the Bell Laboratories in 1974. The resulting program prints "hello, world" on the computer screen. Simple C-language source code example, a procedural programming language.