建立表达式语法树及相关操作，根据输入的表达式，建立语法树，并进行遍历输入横置的树-establish regular expression syntax tree and related operations, according to the importation of expression, the establishment of syntax tree, and traversing the tree importation Workspace

用动态规划解决背包问题，采用递归和非递归两种方式实现，递归过程中保留中间结果以减少复杂度-Dynamic Programming Knapsack Problem

一些入门的c++编程例程：数组、指针、引用、类、循环、逻辑表达、友元等-Some started c++ programming routines: arrays, pointers, references, classes, cycling, logical expression, friend, etc.