I want to achieve an effect:
Console:
2012.223 + 3132.21 * {91-33/(23 + 43.312) + 31} - 99
484.1065722=382
Input expression, illegal reply=Error, legal reply results:
Now realize matching Numbers (with +/-, decimal and decimal point, etc., shall not take I (imaginary))
ExpressionEvaluation. Main. Java

 
Package ExpressionEvaluation; 

import java.util.*; 
Import the Java. Util. Regex. *; 

The import tree. *; .//the tree Node. Java and tree. The tree. The Java own compiled 

Public class Main 
{
Public static void the output (String line) 
{
System.out.println(line); 
} 
Public static String input () 
{
Scanner s=new Scanner (System. In); 
The String line=s.n extLine (); 
The return line. 
} 
Public static Boolean match (the Pattern PTN, String STR) 
{
The Matcher m=PTN Matcher (STR); 
A Boolean flag=m.m atches (); 
Return flag; 
} 
Public static void main (String args []) 
{
String number_str=(\ \ "+ | -)? (1-9] [\ \ d * \ \.? \ \ d *) | (0 \ \. \ \ d * (1-9]) "; 
The Pattern number=Pattern.com running (number_str); 

String STR=input (); 

System. The out. Println (match (number, STR)); 
} 
} 

tree. Node. Java

 
Package tree; 

import java.util.ArrayList; 

Public class Node 
{
The public type data=https://bbs.csdn.net/topics/null; 
Public Node Father=null; 
Public ArrayList The children=new ArrayList (a); 
@ Override 
Public String toString () 
{
Return the data. The toString (); 
} 
Public void addChild (Node Child) 
{
Children. The add (child); 
} 
Public void addChild (Node The child, int index) 
{
Children. The add (index, child); 
} 
Public void setChild (Node The child, int index) 
{
Children. The set (index, child); 
} 
Public Node GetChild (int index) 
{
Return the children. Get (index); 
} 
} 

tree. The tree. The Java

 
Package tree; 

import java.util.ArrayList; 
The import tree. The Node; 

Public class Tree 
{
Private Node The root=new Node (a); 
Public Tree () 
{
//pass 
} 
Public Tree (type rdata) 
{
Root. Data=https://bbs.csdn.net/topics/rdata; 
} 
Public Node GetRoot () 
{
Return the root; 
} 
}