说明：  本电子文档详细讲述了C语言的学习内容，包括各种算法，变量，数组，函数，结构，指针，字符串，预处理，输入和输出等内容
(The electronic document to describe in detail the C language, including a variety of algorithms, variable, array, function, structure, pointer, strings, pre-processing, input and output, etc.)