out.txt

编译器模拟程序

词法分析结果： 
	1: (
	1: *
	1: (
	1: +
	1: (
	1: *
	1: NUM val = 1
	1: NUM val = 2
	1: )
	1: (
	1: +
	1: NUM val = 3
	1: NUM val = 4
	1: )
	1: )
	1: (
	1: +
	1: (
	1: -
	1: NUM val = 6
	1: NUM val = 5
	1: )
	1: (
	1: +
	1: NUM val = 7
	1: NUM val = 8
	1: )
	1: )
	1: )
	2: EOF
转换为正常算术表达式： 
1	*	2	+	3	+	4	*	6	-	5	+	7	+	8	
最终计算结果： 144
打印语法树（按层打印对应不是很整齐）： 

*
+	+	
*	+	-	+	
1	2	3	4	6	5	7	8