The following procedure is intended to return the number of times the value val appears in the list myList. The procedure does not work as intended.

Question

W Mark for Review
Which of the following changes can be made so that the procedure will work as intended?
Changing line 6 to IF (item = count)
Line 1:
Line
2:
{
Line 3:
Line 4:
Line 5:
Line 6:
Line 7:
Line 8:
Line 9:
Line 10:
Line 11:
Line 12: }
PROCEDURE countNumOccurrences(myList, val)
FOR EACH item IN myList
count + 0
IF (item = val)
{
count - count + 1
}
RETURN( count)
® Changing line 6 to IF(myList[item] = val)
© Moving the statement in line 5 so that it appears between
lines 2 and 3
D
Moving the statement in line 11 so that it appears between lines 9 and 10

Answer 1

The procedure you've provided seems to have issues with how it initializes and updates the count variable, among others. Let's analyze each of the suggested changes to identify which one would correct the logic:

Current Issues in the Code:

1. Initialization of count: In line 5, the operation count + 0 does not effectively initialize count. It should rather be something like count = 0.
2. Updating count: The line count - count + 1 is logically incorrect. It should be count = count + 1 or simply count += 1.
3. Return statement: The indentation or placement might create confusion but that's secondary compared to the primary logic issues.

Given your options for change:

Suggested Changes:

1. Changing line 6 to IF (item = count): This makes no sense in the context. You want to check if item is equal to val, not count. So this won't fix the procedure.

2. Changing line 6 to IF(myList[item] = val): This is incorrect. In the context of a loop iterating through myList, item represents the actual value, not an index. So, this change wouldn't work either.

3. Moving the statement in line 5 so that it appears between lines 2 and 3: This would correctly initialize count to 0 before the loop begins. This change addresses the initialization problem identified earlier.

4. Moving the statement in line 11 so that it appears between lines 9 and 10: This change would affect the flow of returning count, and it doesn't address any of the initialization or updating problems.

Conclusion:

The best option is: Moving the statement in line 5 so that it appears between lines 2 and 3.

Additionally, you'd also need to correct line 6 (where you check and increment count) to use the correct condition and increment operation:

• Change it to count = count + 1 or count += 1.

The corrected pseudocode would look something like:

PROCEDURE countNumOccurrences(myList, val)
{
    count = 0                            // Initialize count
    FOR EACH item IN myList
    {
        IF (item = val)                  // Compare with val
        {
            count = count + 1            // Increment count
        }
    }
    RETURN(count)
}

To recap, the main change you need to ensure is that count is initialized properly and updated correctly inside the loop.