The data type identification function based on finite state machine (2)

The initial array and each flag

. 1      Private  Final  int [] [] State_table;
 2      Private  int Now_state = 0 ;
 . 3      Private  Final  int Char_m = 0; // represents 0-9 49-48 
. 4      Private  Final  int Char_d =. 1; // represents 45 characters. 
. 5      Private  Final  int Char_e = 2; // represents the character e 69/101 
. 6      Private  Final  int Char_j =. 3; // represents - character 46 is 
 . 7      // spaces 32 
. 8      
. 9      Private  Final  int=. 1 Int_result_code; // Integer 
10      Private  Final  int Float_result_code =. 3; // float 
. 11      Private  Final  int Scientif_result_code =. 6; // scientific notation 
12 is      Private  Final  int Scientif_result_code_2 =. 7; // scientific notation
 13      // 0245 state is not output

State_table two-dimensional array is referred to in the previous chapter, for storing each state and the corresponding conversion relationships.

Now_state shows a state in which the current, where the state is initialized to 0.

The vertical axis represents the value of each Char_ *

The remaining output indicates the state can

Array initialization

 1 FSM(){
 2     State_table=new int[8][4];
 3     int[] b={1,1,3,3,7,6,6,7};
 4     
 5     for(int i=0;i<8;i++)
 6     Arrays.fill(State_table[i],-1);//填满
 7     State_table[1][1]=2;
 8     State_table[1][2]=4;
 9     State_table[3][2]=4;
10     State_table[4][3]=5;
11     for(int i=1;i<=8;i++)
12         State_table[i-1][0]=b[i-1];            
13     }

My name is called FSM class so this is a constructor

Use Arrays.fill can easily fill all the array -1. However, this method only supports an array. So here we use a for loop to iterate over an array of 8

The final array like this

1　　-1　　-1　　-1

1　　 2　　 4　　-1

3　　-1　　-1　　-1

3　　-1　　 4　　-1

7　　-1　　-1　　 5

6　　-1　　-1　　-1

7　　-1　　-1　　-1

Analyzing the input line and each character belonging to (0 or 1? 2? 3?) 0123 corresponding to the defined at the outset Char_ *

 1     //对输入的字符串进行类型判断
 2     public void Input_Classificantion(String Nowline){        
 3         for(int i=0;i<Nowline.length();i++) {            
 4             if(Nowline.charAt(i)>='0'&&Nowline.charAt(i)<='9')
 5                 Change_state(Now_state,Char_m );
 6             else if(Nowline.charAt(i)=='.')
 7                 Change_state(Now_state, Char_d);
 8             else if(Nowline.charAt(i)=='e'||Nowline.charAt(i)=='E')
 9                 {    Check_science(Nowline,i);
10                     Change_state(Now_state, Char_e);
11                 }
12             else if((Nowline.charAt(i)=='-'))
13                 Change_state(Now_state, Char_j);
14             else if(Nowline.charAt(i)==' ') {
15                 //排除同行的空格
16                     do {
17                         i=Nowline.indexOf(' ',i)+1;}
18                     while(Nowline.charAt(i)==' ');
19                     i--;
20                     Input();
21                 }
22 is              the else  
23 is                  {System.out.println ( "input contains illegal characters" );
 24                  Erroe_code =. 1 ;}        
 25          }
 26 is          
27          the Input ();        
 28      }

Here there have been a total of three methods, namely,

Change_state(int Old_state,int Char_code)

Input()

Check_science

Change_state(int Old_state,int Char_code)

This method is used in which the current state and the corresponding two-dimensional table Char_ * using specific implementation as follows

. 1      Private  Boolean the Output = to false ; // whether the output flag 
2      Private  Boolean the Check = to false ; // Check whether the norms written in scientific notation 
. 3      
. 4      Private  int Erroe_code = 0;

1      // to read the corresponding value determined by the current state of the value of the array 
2      Private  void Change_state ( int old_state, int Char_code) {
 . 3          Now_state = State_table [old_state] [Char_code];        
 . 4          
. 5          IF (Now_state Now_state == 0 || || 2. 4 Now_state == == || == Now_state. 5) // non-output state                                      
. 6              the output = to false ;
 . 7          the else  IF (Now_state == -. 1 ) {
 . 8                  System.out.println ( "input error" );
 . 9                  Erroe_code = 2 ;
 10                 System.exit (. 1 );
 . 11              }
 12 is          the else  // output state 
13 is              the Output = to true ;
 14          
15      }

Input（）

1      // The type of the current state of the output corresponding to this state 
2      Private   void the Input () {
 . 3          IF (the Output == to true ) {
 . 4              IF (Now_state == Int_result_code) 
 . 5                  System.out.println ( "integer" );
 . 6              the else  IF (Now_state == Float_result_code)
 . 7                  System.out.println ( "float" );
 . 8              the else  IF (the Check) {
 . 9                  IF (Now_state == Scientif_result_code)
 10                  negative System.out.println ( "scientific notation " );
 11                 the else  IF (Now_state == Scientif_result_code_2)
 12 is                  System.out.println ( "scientific notation" );
 13 is              }
 14              the else  
15                  System.out.println ( "scientific notation format error" );
 16          }
 . 17          the else {
 18 is              the System. out.println ( "input error" );
 . 19              Erroe_code = 2 ;
 20 is              System.exit (. 1 );
 21 is          }
 22 is          Now_state = 0 ;
 23 is      }
 24

Check flag which represents the scientific notation format compliance