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What is the index of the first character in a string?



The Current Character

Updating the current character is done as follows:

  public boolean recognize(String str)
    final int reject = 3;
    int  state = 0;
    char current;
    int  index = 0

    while ( ... )
      current = str.charAt( index++ );

      . . . . .


Recall that index++ adds one to index after using it.

It is good practice to get the current character at just one place in the code, usually at the top of a loop. This makes the translation from automaton to code easier, and makes the code more readable.

Now we need to deal with:

    while ( ... )


Either one of two conditions will stop the automaton. What are those conditions? (You may wish to look at the diagram of the finite automaton ).