Radio Shack TRS-80 Model 100 Basic Manual page 148

After the program is entered, execute it. The output should appear as:
MED I AN SALES
MON
288.5
TUE
272.5
WED
325
THU
285
FRI
256.5
The median for each day of the week is printed below the name of the day. For each
day, the six sales values are sorted and the median computed by averaging the two
middle values.
Line 5 The OPEN statement allows the data to be read from a RAM file.
Line Ht The numeric variable N is assigned the value 6, indicating six weeks of data
for each day of the week.
Lines 28 - 48 The data is read from RAM and stored in the two dimensional array R.
Note that a dimension (DIM) statement was not required in this case since no subscript
value will exceed
9.
Line 58" The first FOR statement in this line begins a loop that calculates the median
for each day of the week. Since there are five days, the index variable D runs from 1
to 5.
The second FOR statement in this line begins a loop that transfers the six weeks of
data for day into a single dimension array S.
Line 68 For a given week Wand day of the week D, the data value is transferred
from the two dimensional array R into the one dimensional array S. The data for the
first week will be transferred to SO)' the second week to S(2) and so on.
Line
78
The inner loop which transfers the six data values from the two dimensional
array to the one dimensional array is terminated.
Line 88 This line contains a new statement: GOSUB. When this statement is
executed, the program jumps to line 500. Lines 500 through 570 sort and compute the
median of the one dimensional arrays S. The median is stored in the variable MD (line
560). When line 570 is executed, the program jumps back to the statement following
the GOSUB statement. The block of statements in lines 500 through 570 are called a
subroutine. This particular subroutine computes the median of the one dimensional
array
8(1), 8(2), ... 8(N).
The value of the median is stored in the variable MD. It was necessary, in lines 50 -
70 , to store column D of the two dimensional array R in the one dimensional array S
because the subroutine computes the median of this specific one dimensional array.
Line 98 The value of the median for day D, which was placed in the variable MD in
the subroutine, is stored in the array M(D). This is done hecause the next median
calculated will be placed in MD, replacing the previous value of MD, before the
program displays the result.
Line
lee
This line terminates the FOR / NEXT loop which began in the first FOR
statement in line 50.
Line 118 The heading MEDIAN SALES is displayed. The TAB function is used to
center the heading.
142