Source code
Source code is the human-readable text written by computer programmers using a programming language. It contains the instructions and definitions for a computer program. Source code is designed to be easily understood and modified by humans, serving as the original form of software before it is translated into a format that a computer can execute.
It is the foundational element of software development and is essential for understanding, maintaining, and evolving software applications.
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Overview and Purpose
The primary purpose of source code is to allow programmers to express the logic and functionality of a software program in a way that is comprehensible to them. Programming languages provide structured syntax and concepts that enable developers to write complex instructions relatively clearly.
Source code files are typically plain text files that can be viewed and edited using simple text editors or specialized Integrated Development Environments (IDEs). They represent the creative and intellectual work involved in building software.
Source Code vs. Executable Code
It is crucial to distinguish source code from the form of the program that the computer's CPU can actually run:
- Source Code
- - Human-readable text written in a Programming language.
- - Cannot be directly executed by the CPU.
- - Must be translated.
- - Examples: .c files (C), .py files (Python), .java files (Java), .html files (HTML is technically markup, but often edited as source).
- Machine Code / Executable Code
- - Binary instructions (sequences of 0s and 1s) that the CPU can directly understand and execute.
- - Difficult or impossible for humans to read or write directly.
- - Produced from source code through a translation process.
- - Examples: .exe files (Windows), executable files without extensions (Linux/macOS), .dll or .so library files.
How Source Code is Written
Programmers write source code using various tools:
Text Editors: Simple programs for editing plain text files (e.g., Notepad, nano, Vim). Integrated Development Environments (IDEs): More sophisticated software suites that combine a text editor with features like syntax highlighting, code completion, debugging tools, and integration with compilers or interpreters. Source code is written following the rules (syntax and semantics) of a specific Programming language, such as Python, Java, C++, JavaScript, etc. Different languages are suited for different types of tasks and development styles.
Here is a simple example of source code in Python, designed to print "Hello, World!" to the console: <syntaxhighlight lang="python"> print("Hello, World!") </syntaxhighlight>
The Translation Process
Computers cannot directly execute human-readable source code. It must be translated into machine code or an intermediate format. This translation is done by either a Compiler or an Interpreter:
- Compilation
- A compiler reads the entire Source code of a program and translates it into machine code or object code before the program is run. The result is typically an executable file that can be run independently of the compiler. Compilation usually results in faster execution.
- - Languages often compiled: C, C++, Java (compiles to bytecode, then JIT-compiled), Go.
- Interpretation
- An interpreter reads and executes the Source code line by line at runtime. The interpreter translates each line into machine code as it is needed. No separate executable file is created. Interpretation is often more flexible for development and testing but can be slower than running compiled code.
- - Languages often interpreted: Python, JavaScript, Ruby, PHP.
Some languages use a combination of compilation and interpretation (like Java or C# which compile to bytecode that is then interpreted or JIT-compiled).
Importance of Source Code
Having access to the source code of a program is important for several reasons:
Understanding: Allows programmers to understand the logic, algorithms, and implementation details of the software. Modification and Customization: Enables developers to change the software's behavior, add new features, or adapt it to specific requirements. Bug Fixing: Necessary to identify and correct errors (bugs) in the software. Porting: Allows the software to be adapted to run on different computer architectures or operating systems. Education: Studying source code is a fundamental way to learn programming and Software engineering. Auditing: Enables security experts and users to audit the code for vulnerabilities or unintended functionality (key for Open-source software). The availability of source code is the defining characteristic of Open-source software, providing users with the freedom to inspect, modify, and share the software. In contrast, proprietary software vendors typically distribute only the executable code, keeping the source code confidential.
See also
External links
Webopedia: Source Code TechTarget: Source code GeeksforGeeks: Difference between Compiler and Interpreter ]]
