Convert program code into machine-readable machine code

Convert source code into another programming language

Convert one human language into another one

Executes the program source code

Because most programmers program in a high-level language

Because most programmers program in a low-level language

Because there are many different human languages

assembler

interpreter

compiler

assembler

interpreter or compiler

High-level source code

Low-level source code

Object code

Machine code

High-level source code

Assembly code

Object code

Machine code

High-level source code

Assembly code

Low-level source code

Machine code

Program executes faster

Can keep source code secret

More portable as can produce intermediate bytecode

Debugging tends to be easier

Detects errors as they arise at run-time

Easier to keep source code secret

More portable as can produce intermediate bytecode

Debugging tends to be easier

Source code is compiled at run-time

Source code is compiled before run-time

a combination of compiling and interpreting

Source code is compiled after run-time

Nature of the task

Availablity of a compiler

Whether language is compiled or interpreted

Popularity of programming language