从标准输入输出读取字符，从标准输入输出输出字符-Read characters from standard input and output, the output from the standard input and output character

系统辨识初学者对辨识的认识以及对于LS算法的初级了解，对于最小二乘法的学习奠定基础-System identification for beginners to understand the recognition and the primary understanding of the LS algorithm, the least square method of learning to lay the foundation