中文说明：这是决策树分类的的最经典的源码，同学们可以在此基础上学习和修改，入口程序已经写好，需要其他方法可以自己添加，其中Predict和train分别代表训练集算法和预测算法，数据集没放。但是可以处理一般的问题。供大家修改和使用！！！
English Description：
This is the most classic source code of decision tree classification, students can learn and modify on this basis, the entry program has been written, you need other methods to add, in which predict and train represent the training set algorithm and prediction algorithm respectively, and the data set is not put. But it can deal with general problems. For everyone to modify and use!!!