ISTQB CTAL-TTA Exam - Topic 6 Question 33 Discussion

Actual exam question for ISTQB's CTAL-TTA exam

Question #: 33
Topic #: 6

[All CTAL-TTA Questions]

Given the following pseudo code for a program to solve quadratic equations:

program Quadratic Formula

integer: a, b, c, d

floating point: r1, r2

READ (a)

READ (b)

READ (c)

d := (b * b) - (4 * a * c)

IF d < 0 THEN

PRINT ("Imaginary Roots")

ELSE

r1 := (-b + sqrt(d)) / (2 * a)

r2 := (-b - sqrt(d)) / (2 * a)

PRINT ("first root is: " r1)

PRINT ("second root is: " r2)

ENDIF

END program Quadratic_Formula

Which of the following checklist items is MOST likely to indicate a problem in this program?

ADoes the code avoid comparing floating point numbers for equality?

BAre all variables properly defined with meaningful, consistent and clear names?

CAre there any redundant or unused variables?

DAre divisors tested for zero or noise?

Show Suggested Answer

Suggested Answer: D

Analysis:

The given pseudo code for solving quadratic equations includes operations that involve division. One of the critical issues in such operations is ensuring that the divisor is not zero, which would result in a division by zero error.

Checklist Item:

D . Are divisors tested for zero or noise?:

This checklist item addresses the potential problem of dividing by zero. In the pseudo code, the variable a is used as a divisor in the formula (-b sqrt(d)) / (2 * a). If a is zero, this will result in a division by zero error. Therefore, it is crucial to test whether a is zero before performing the division.

Explanation of Incorrect Options:

A . Does the code avoid comparing floating point numbers for equality?:

This is important but not directly relevant to the given pseudo code's primary issue.

B . Are all variables properly defined with meaningful, consistent and clear names?:

This is good practice but does not address the critical issue of division by zero.

C . Are there any redundant or unused variables?:

Identifying unused variables is helpful for code clarity but does not address the primary functional issue in the pseudo code.

The ISTQB CTAL-TTA syllabus and standard code review practices emphasize the importance of ensuring safe arithmetic operations, particularly avoiding division by zero.

Sources:

ISTQB-CTAL-TTA Syllabus

General knowledge on code review and arithmetic operations.

by Dewitt at Mar 19, 2025, 12:40 AM

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Elbert

3 months ago

Totally agree, A is the most critical issue here.

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Eileen

3 months ago

I think variable names could be clearer.

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Oliva

3 months ago

Imaginary roots? That's wild!

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Cordelia

4 months ago

Wait, does it really handle all edge cases?

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Justa

4 months ago

Definitely need to check for zero divisors!

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Janey

4 months ago

Option D stands out to me because I recall that dividing by zero can cause errors, so it’s crucial to test for that in any program.

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Goldie

4 months ago

I’m a bit confused about option C; I don’t see any unused variables, but I guess it’s worth double-checking.

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Cristina

4 months ago

I remember practicing a question about variable naming conventions, so option B seems relevant, but I feel like the names here are pretty straightforward.

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Melissa

5 months ago

I think option A might be a concern since comparing floating point numbers can lead to inaccuracies, but I'm not entirely sure how it applies here.

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Theodora

5 months ago

Comparing floating-point numbers for equality is always tricky, so that's probably the most likely issue to watch out for. I'd spend some time thinking through how to handle that properly.

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Chi

5 months ago

The code looks good overall, but I'd be sure to test the edge cases, like when the discriminant is exactly 0. Gotta make sure we're handling all possible scenarios.

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Alaine

5 months ago

Hmm, the variable names seem clear enough, but I'd double-check that they're all being used consistently throughout the code. Wouldn't want any typos or unused variables.

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Alida

5 months ago

This looks like a pretty straightforward quadratic equation solver. I'd focus on checking for potential division by zero and handling imaginary roots properly.

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Leota

11 months ago

Hmm, the variable names could use some work. 'a', 'b', and 'c' are a bit cryptic. How about 'coefficient_a', 'coefficient_b', and 'constant_c' instead?

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