将两个带头结点的有序循环链表合成一个带头结点的有序循环链表。

实验内容：使用键盘输入表达式，计算表达式的值并输出；将表达式转化成后缀表达式输出，利用后缀表达式求表达式的值并输出

-The two take the lead in the ordered circular list node synthesis of a lead in the ordered circular list node. Experiment: use the keyboard to enter an expression to calculate the value of the expression and output　the expression into postfix expression output, using postfix expression evaluation and the output value of the expression