Source code (or code)

Any collection of text, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a computer program is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source code.

I think it’s sort of text representation of algorithm, written in programming language.

Source code is often transformed by an assembler or compiler into binary machine code, which can be executed by computer.

In other words program (which now executed from machine code) translate source code written by human into machine code, which can be executed by computer to perform some actions (solve computational problem as example).

As example, you can write some compiler program (source code) for new programming language, by using one of existing compiler/programming language, and then that program can translate your new programming language (your own source code) into machine code, which can be executed by computer. This process named bootstrapping.

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Source code -> | Compiler | -> Machine code
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Goals of source code:

• correctness
• design, subjective
• style, such as readability, maintainability, extensibility, etc.