本文件为单片机C语言之C51部分教程。总共有五节课：第一课：数据类型　第二课：常量　第三课：变量　第四课：运算符和表达式　第五课：语句。对于单片机C语言初学者来说，不失为一本较好的入门教程。-this document for SCM C51 C language part tutorial. A total of five classes : first class : data types second lesson : Constants third lesson : Variable fourth lesson : Operators and expression fifth lesson : statement. SCM C language for beginners, after all, a good introductory tutorial.