15.2 Using Format Strings
  Format strings determine the way in which items are to be
  printed in the output file. Format strings can be any of the
  following:

  .
        String variables
  .
        String literals
  .
        Named string constants
  .
        A combination of the previous strings

  The PRINT USING statement must contain one or more
  format strings. Each format string is made up of one for-
  mat field . Each format field controls the output of one print
  item and can contain only certain characters, as described
  throughout the chapter.

  The PRINT USING statement must also contain a list of
  items you want printed. To format print items, you must
  separate them with commas or semicolons. Separators be-
  tween print items do not affect output format as they do with
  the PRINT statement. However, if a comma or semicolon
  follows the last print item, BASIC does not return the cursor
  or print head to the beginning of the next line after it prints
  the last item in the list.

  When BASIC encounters an invalid character within the
  current format field, it automatically ends the format field.
  Therefore, you do not need to delimit format fields. The
  character that terminates the previous field can be either a
  new format field or a string literal.

  In the following example, the first three characters in the
  format string (###) make up a valid numeric format field.
  The fourth character ( A ) is invalid in a numeric format
  field; therefore, BASIC ends the first format field after the
  third character. BASIC continues to scan the format string,
  searching for a character that begins a format field. The first
  such character is the number sign at character position 7.
  Therefore, the characters at positions 4, 5, and 6 are treated
  as a string literal. The characters at positions 7, 8, and 9
  make up a second valid numeric format field.
  PRINT USING "###ABC###", 123, 345

  Output
  123ABC345
  When the statement executes, BASIC prints the first number
  in the list using the first format field, then prints the string
  literal ABC, and finally prints the second number in the list
  using the second format field. If you were to supply a third
  number in the list, BASIC would reuse the first format string.
  This is called reversion .
  PRINT USING "###ABC###", 123, 345,
  564

  Output
  123ABC345
  564ABC
  Because any character not part of a format field is printed
  just as it appears in the format field, you can use a space or
  multiple spaces to separate format fields in the format string
  as shown in the following example:
  DECLARE STRING CONSTANT format_string = "###.## ###.##"
  DECLARE SINGLE A,B
  A = 2.565
  B = 100.350
  PRINT USING format_string, A, B, A, B

  Output
      2.57 100.35
      2.57 100.35
  When the BASIC compiler encounters the PRINT USING
  statement, BASIC prints the value of A (rounded according
  to PRINT USING rules), three spaces, then the value of B .
  BASIC prints the three spaces because they are treated as a
  string literal in the format string. Notice that when BASIC
  reuses a format string, it begins on a new line.