public class Lex {
public Lex() {
   input = nextInput();
   state = 1;
   }

// inputs 
final int ZERO = 0; final int ONE = 1; final int TWO = 2; 
final int POINT = 3; final int STAR = 4; 
// actions
final int NEXT = 0; final int RETURN = 1; final int BACK = 2; final int ERROR = 3; 
// lexemes
final int REAL = 0; final int MULT = 1; final int EXP = 2;

private int state;
private int table1 [] []; // first index is current state, second is input
private int table2 [] []; // first index is current state, second is input

private int input; 
private int nextInput(){ . . . } // assigns the next character to c

//initialize table1 and table2
	
public int nextLexeme() {
   state = 1;
   // reading loop
   while (true) {	 
      switch (table1[state][input]) {
         case NEXT: state = table2[state][input]; input = nextInput();
             // a normal state transition
         case RETURN: input = nextInput(); return (table2[state][input]);  
             // a lexical category is completed (including the last character read)
         case BACK: return (table2[state][input]); 
             // a lexical category is completed (the last character read is not included)
         case ERROR: return(0);  // the last character read represents an error
         }
   }
}
}