Line 559 The numeric function INT is used
in
this line. This function drops any
fractional part of a number and thus returns the greatest integer less than
or
equal to
the argument. Consider the following examples
Argument x
1.234
239.899
4
Value of INT(x)
1
239
4
The values that are computed and assigned
to
the variables
Nl
and
N2
are the middle
values for the subscripts of the array
S(I)
through SeN).
For example, if N has the value 16, then
(N + 1) / 2 = 8.5
(N
+
2)
/ 2 = 9
and
INT((N + 1) / 2) = 8
INT((N
+ 2) / 2) = 9
so
that N1 and N2 will correctly contain the middle subscript values. Additional
examples are given in the table below:
N
30
20
13
27
(even)
(even)
(odd)
(odd)
N1
15
10
7
14
N2
16
11
7
14
Note that when N is even,
Nt
and
N2
are the two middle values and when N
is
odd,
Nt and
N2
are both equal
to
the single middle value. Thus, the use of the INT
function avoids any testing
to
determine whether N is even or odd.
Line
569 The median is calculated in this line.
If
N is even, then the average
of
the
two middle values
is
computed. If N
is
odd, then the values stored
in
NI and
N2
are
the same and so the median is correctly calculated
as
the middle value.
Line
579 The median
is
displayed.
Now that you have a program which will sort an array of arbitrary length and compute
the median, you can use it
as
a sUbprogram in larger programs. The next experiment
shows you how to do this.
Experiment
#7
Calculating the Median
for Each Weekday
In
this experiment, the median sales will be calculated for each day of the week. This
means that the program should compute the median value of the six Monday sales, the
median value of the six Tuesday sales, and so on for each
day
of
the week.
To accomplish this, the six values for each day must be sorted before the median can
be computed. The following program illustrates an efficient method
of
doing this.
140
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