Question

Consider the code segment below.

Line 1: IF (b ≠ 0)
Line 2:
Line 3: a ← a/b
Line 4:
Line 5: ELSE
Line 6:
Line 7: a ← a*b
Line 8:

Which of the following changes will NOT affect the results when the code segment is executed?
1) Changing line 1 to IF (b = 0)
2) Changing line 3 to a ← a*b
3) Changing line 5 to ELSE IF (b ≠ 0)
4) Changing line 7 to a ← a/b

Answer 1

The proposed change that will NOT affect the results when the code segment is executed is changing line 7 to 'a ← a/b' because performing the same operation of division in the ELSE block as in the IF block results in no change to the output.

Step-by-step explanation:

The student has provided a code segment with a conditional statement and is asking which of the proposed changes will NOT affect the results when the code is executed. Looking at the code segment, each change has a different impact:

1. Changing line 1 to IF (b = 0) will change the condition under which the IF block executes, thus affecting the result.
2. Changing line 3 to a ← a*b alters the operation performed within the original IF block, also affecting the result.
3. Changing line 5 to ELSE IF (b ≠ 0) makes the ELSE block only execute under certain conditions, which could change the result depending on the value of b.
4. Changing line 7 to a ← a/b would result in the same operation as line 3, leaving the overall result unchanged for the ELSE block.
5. Therefore, the change that will NOT affect the results when the code segment is executed is the last one, changing line 7 to a ← a/b. This is due to the fact that multiplication or division by the same number on both sides of an equation does not change equality.