What process turns high-level code into executable code?

The process that turns high-level code into executable code is known as compilation.

In the realm of computer science, the transformation of high-level code, which is human-readable, into executable code that a machine can understand and execute, is achieved through a process called compilation. This process is carried out by a special program known as a compiler. The compiler is a crucial tool in software development as it bridges the gap between human programmers and the machine's binary language.

High-level code is written in high-level languages such as Python, Java, C++, among others. These languages are designed to be easily understood by humans, with syntax and commands that resemble natural language. However, computers cannot understand these languages directly. They only understand machine code, which is a series of binary instructions. Therefore, there is a need to translate the high-level code into machine code, and this is where the compiler comes in.

The compiler works in several stages. First, it scans the entire high-level code to understand its structure and syntax in a phase known as lexical analysis. It then parses this code, checking for any syntax errors and building a tree-like representation of the code. This is followed by semantic analysis, where the compiler checks the code for semantic errors and ensures that it adheres to the rules of the programming language.

After these analysis stages, the compiler proceeds to the optimisation stage. Here, it makes changes to the code to improve its efficiency without altering its functionality. This could involve removing redundant code or reordering instructions for better performance.

Finally, the compiler generates the machine code in the code generation stage. This is the executable code that the computer can run. It is worth noting that the machine code is specific to the computer's processor architecture, meaning that a program compiled for one type of processor may not run on a different type.

In summary, the compilation process is a crucial step in software development that transforms high-level, human-readable code into machine-executable code. It involves several stages including lexical analysis, parsing, semantic analysis, optimisation, and code generation.