Decomposition and algorithm practice questions
Every programming problem needs decomposing so that it can be properly understood. From this, an algorithm can be designed and tested.
Part of
Designing an algorithm
Algorithm design option one - flow diagram
Algorithm design option two - pseudo-code
wet_calc ← 1.5
OUTPUT “What speed is the go-kart travelling at?”
speed ← USERINPUT
WHILE (speed IS NOT integer) OR (speed < 10) OR(speed > 50) DO
OUTPUT “Speed must be a whole number between 10 and 50. Try again.”
speed ← USERINPUT
ENDWHILE
OUTPUT “Is the ground wet? (yes/no)”
wet_ground ← USERINPUT
IF wet_gound = “yes” THEN
braking_dist ← (speed * 5)* wet_calc
ELSE
braking_dist ← speed * 5
ENDIF
OUTPUT “The braking distance is: “ + braking_dist + “m”
Testing table
Tests will be required to test that the final program runs correctly.
| Test no | Description | Test data | Test type | Expected outcome |
|---|---|---|---|---|
| 1 | Calculate normal speed on dry ground | 20, no | Normal | 100m |
| 2 | Calculate normal speed on wet ground | 20, yes | Normal | 150m |
| 3 | Borderline calculate normal speed on dry ground | 10, no | Boundary | 50m |
| 4 | Borderline calculate normal speed on wet ground | 10, no | Boundary | 75m |
| 5 | Test rejected input - below minimum | 5, yes | Erroneous | Asked to input again |
| 6 | Test rejected input - above maximum | 100, yes | Erroneous | Asked to input again |
| 7 | Test rejected input - not a number | ten, yes | Erroneous | Asked to input again |
The problem has now been fully decomposed and an algorithm has been designed.