What Is Source Code?

Source code is the human-readable set of instructions written in a programming language that tells a computer how to perform specific tasks.

Programmers typically write source code using programming languages (like C++ or Python) and a text editor or an integrated development environment (IDE), which can offer helpful features like syntax highlighting, auto-completion and debugging tools.

While a simple program’s source code may be stored in a single file, larger programs are usually broken into multiple files to improve organization and maintainability. Programmers often use version control systems, such as Git, to track code changes and collaborate across teams.

Source Code Example 

One of the simplest programs out there, and one that’s familiar to almost anyone with experience in programming is the “Hello, World!” program, which simply outputs (or displays) the message “Hello, World!” when executed.

“Hello, World!” programs are commonly used as introductory examples when programming is taught; it is typically the first thing a student learns when studying programming.

Source Code Example in Python

As an example here is a “Hello, World!” program in Python:

print("Hello, World!")

Source Code Example in C++

And here is one version of it in C++:

#include <iostream>

int main()
{
  std::cout << "Hello, World!\n";
  return 0;
}

RelatedPython Pathlib Is Better Than the OS Module. Here’s How to Use It.

How Does Source Code Work?

Even without programming experience, the “Hello, World!” examples above are easy to follow. When run, a program typically executes sequentially — line by line, top to bottom — though the actual flow can vary based on control structures, function calls and the programming language being used. While the C++ version may look more complex, both examples are designed to do the same thing: display the message “Hello, World!”

Before a computer can run source code, it must be translated into machine-readable instructions. This happens through either a compiler or an interpreter, depending on the language. The result — often called object code when compiled — consists of low-level binary instructions the processor can execute.

Why Is Source Code Important?

The most important aspect of source code is that it provides the basic foundation for creating software. This feature of source code extends to other use cases as well. For example, source code allows for editing, customizing or developing the software further. Without access to the source code, modifying or extending software functionality becomes significantly more difficult, and in many cases, impractical.

For all the reasons outlined above, a program’s source code makes it easier to develop similar software for other operating systems while also making it possible for multiple people (or even a large community) to co-develop software.

Alternatives to Writing Source Code

You might think that writing source code is the only way to create a program. However, there now exist other alternatives to programming as well.

Visual Programming Tools

Visual programming tools allow users — including non-programmers — to create software using graphical elements instead of writing traditional code. Often this means the program uses block diagrams of some sort to display the program’s flow or behavior. Visual programming tools can be “no-code,” meaning they require no traditional coding and often do not allow it at all. Alternatively, visual programming can be “low-code,” meaning that, while writing source code may or may not be required, you can use it to expand the functionality of the visual programming tool. Examples of visual programming tools include LabVIEW, Simulink and Bubble.

Cell-Based Programming Tools

You can also use cell-based programming tools, such as Excel or Google Sheets, wherein commands and instructions are written into the cells of a spreadsheet.

Frequently Asked Questions