An atmospheric research drone records six barometric pressure measurements at different altitudes and stores them in an array called pressure_readings.
A developer writes a bubble sort algorithm to sort these measurements in descending order:
1 pressure_readings[0] ← 1013.2
2 pressure_readings[1] ← 1008.5
3 pressure_readings[2] ← 1015.1
4 pressure_readings[3] ← 995.4
5 pressure_readings[4] ← 1002.3
6 pressure_readings[5] ← 991.0
7 FOR pass_idx ← 0 TO 4
8 FOR scan_idx ← 0 TO 4
9 IF pressure_readings[scan_idx + 1] > pressure_readings[scan_idx] THEN
10 temp ← pressure_readings[scan_idx]
11 pressure_readings[scan_idx] ← pressure_readings[scan_idx + 1]
12 pressure_readings[scan_idx + 1] ← temp
13 ENDIF
14 ENDFOR
15 ENDFOR
An earlier draft of this algorithm used the following code on line 8:
FOR scan_idx ← 0 TO 5
Explain why this change causes an error when the algorithm is executed.