id3决策树算法，maxlen为数据维数，根绝数据自行修改，根据属性名修改main函数，可运行-id3 decision tree algorithms, maxlen for the data dimension, eradicate data modify, modify the main function according to the attribute name, you can run

rapart函数是R语言中关于建立决策树的函数，利用这个函数源码，我们可以进行决策树分类算法的使用。-rpart is the code which we can use it to create decision tree.