Programming languages are divided into three types: machine language,which is also called an instruction system,is the only one used directly by computers. The assembler language is a kind of symbolic language.

• 程序设计语言分为机器语言、汇编语言和高级语言三类。机器语言是计算机唯一能直接使用的语言，也叫做计算机指令系统。