Compiler

A compiler is a program that translates source code written in a high-level programming language into machine code (or another lower-level form) before the program is run. The whole program is translated at once, producing an executable file or object code.

Compilation usually goes through stages: lexical analysis, parsing, semantic analysis, optimisation and code generation. Errors are reported for the whole program before it runs, and compiled programs generally run fast. C, C++, Go and Rust are typically compiled; Java and C# are compiled to bytecode that a virtual machine then runs.