Building the Password

Answer:

Probably. My taste is to build the string in three steps.

Next, the program builds the password:

    String password = "";
    int j = 0;
    
    while ( j<digits )
    {
      password = password + choices.charAt( rand.nextInt( choices.length() ) );
      j = j + 1;
    }

First the password is initialized to the empty string. Then random characters, selected from choices, are appended to it, one-by-one. The expression

rand.nextInt( choices.length() )

randomly picks an integer from 0 up to (but not including) the length of the choices string. Then that integer is used to select a character from the choices string. Say that the random integer were X. Then

choices.charAt( X )

is character number X in the string choices, where counting starts at zero. This character is appended to the password and the loop repeats. (For more about string methods, see chapter 29.)

QUESTION 16:

About four things happen in one statement, in the above. This can be hard to keep track of. Is the following code fragment equivalent?

    String password = "";
    int j = 0;
    while ( j<digits )
     {
      int range = choices.length();
      int characterNumber = rand.nextInt( range );
      char ch = choices.charAt( characterNumber );
      password = password + ch;
      j = j + 1;
    }