                        INPUT and OUTPUT.
                        

Input is usually from either the keyboard or from a disk file. Output is
to the screen or to a disk file, although other external devices may be
involved.

The standard text-file variables 'Input' and 'Output' are opened
automatically when program execution begins. 'Input' is a read-only file
associated with the keyboard and 'Output' is a write-only file associated
with the display.

There are two input functions, 'Read' and 'Readln', which are used to read
data from the keyboard. The syntax is:

Read(item,item,...);       or Readln(item,item,...);

where each 'item' is a variable of any integer, real, char, or string type.

Readln is similar to Read except that after reading it skips to the next
line in the file.

There are two output functions , 'Write' and 'Writeln', which are used to
write data to the screen. The syntax is:

Write(item,item,...);       or Writeln(item,item,...);

where each item can be a literal value, such as an integer or a real number,
a character, a string, or a Boolean value. It can also be a named constant,
a variable, a dereferenced pointer, or a function call, as long as it yields
a value that is of type integer, real, char, string, or boolean. The items
are printed on one line, in the order given. The cursor is left at the end
of the line with the function Write, but is moved to the next line with
Writeln. Examples are given on pages 43-45 of the User's Guide (version 6.0).

The Read procedure for text files is of the form:

Read([var f: text;] v1 [,v2,....vn]);    where f is a text-file variable

and the Write procedure for text files is of the form:

Write([var f: text; ] v1 [,v2,...vn]);

or the Readln and Writeln procedures may be used.

See the Library Reference (version 6.0) for further details.


INOUT.TXT
18.4.90
