DEFINITION MODULE RealInOut;
(*
        Terminal input/output of REAL values


From the book 'Programming in Modula-2' by Prof. N. Wirth.
*)

EXPORT QUALIFIED ReadReal, WriteReal, WriteRealOct, Done;

VAR Done: BOOLEAN;

PROCEDURE ReadReal(VAR x: REAL);
(*- Read a REAL from the terminal.
out:    x       the number read.

The syntax accepted is:
["+"|"-"] digit {digit} ["." digit {digit}] ["E"["+"|"-"] digit [digit]]

If a number is found, Done is set to TRUE (otherwise FALSE).
At most 7 digits are significant, leading zeros not
counting.  Maximum exponent is 38. Input terminates
with a blank or any control character.  DEL may be used
for backspacing.
*)

PROCEDURE WriteReal(x: REAL; n: CARDINAL);
(*- Write a REAL to the terminal, right-justified.
in:     x       number to write,
        n       minimum field width.

If fewer than n characters are needed to represent x, leading
blanks are output.
*)

PROCEDURE WriteRealOct(x: REAL);
(*- Write a REAL to terminal, in octal form with exponent and mantissa.
*)

END RealInOut.