Question

How does an interpreter/compiler work? What is the difference between interpreter and compiler.

Answer 1

Compilers

Compilers were the first sort of
translator program to be written. The
idea is simple: You write the program,
then hand it to the compiler which
translates it. Then you run the
result.

Interpreters

An interpreter is also a program that
translates a high-level language into
a low-level one, but it does it at the
moment the program is run. You write
the program using a text editor or
something similar, and then instruct
the interpreter to run the program. It
takes the program, one line at a time,
and translates each line before
running it: It translates the first
line and runs it, then translates the
second line and runs it etc.

Compiler characteristics:

• spends a lot of time analyzing and
  processing the program
• the resulting executable is some form
  of machine- specific binary code
• the computer hardware interprets
  (executes) the resulting code
• program execution is fast

Interpreter characteristics:

• relatively little time is spent
  analyzing and processing the program
• the resulting code is some sort of
  intermediate code
• the resulting code is interpreted by
  another program
• program execution is relatively slow