The CPU only understands machine code, so source code must be translated.

	Compiler	Interpreter
How	translates the whole program once	translates and runs one line at a time
Errors	reports them all at the end	stops at the first error
Output	an executable file	no file: it runs the source directly
Running	fast; no translator needed	slower; the interpreter is needed every time
Source code	stays private	must be shared
Good for	finished software	writing, testing and learning

An assembler translates assembly language into machine code, one instruction for one instruction.