A compiler is a program that translates source code written in one programming language into another language — most often into machine code that a computer’s processor can execute.

Compilation Process

When we write code in a high-level language like C++, Java, or Rust, it cannot be directly understood by the processor. The compiler performs several stages of transformation:

1. Lexical analysis – breaks the code into tokens (words, operators, punctuation).
2. Syntax analysis – checks if the structure of the code matches the grammar of the language.
3. Semantic analysis – validates the logic: variable declarations, type usage, etc.
4. Optimization – improves code efficiency by removing redundancy.
5. Code generation – converts the optimized code into machine code.
6. Linking – connects compiled files together and binds external libraries.

Benefits of Compilation

• Speed – Compiled code runs faster than interpreted code.
• Error Checking – The compiler checks the entire program for errors before running.
• Portability – One source code can be compiled for different platforms.

Examples of Compiled Languages

• C and C++
• Rust
• Go
• Swift

These languages require a compiler like GCC, Clang, or Rustc to convert the source code into an executable program.

Summary

A compiler performs a deep transformation of code — from human-readable form into optimized, executable instructions. Understanding compilation helps developers write more efficient and portable code.