Which type of error is caused by a bug in the program that causes it to operate incorrectly and produce undesired output?

Which type of error is caused by a bug in the program that causes it to operate incorrectly and produce undesired output?

• A. Arithmetic error
• B. Logical error
• C. Semantic error
• D. Truncation error

Answer: (B)

The main idea is that a bug can make the program run but behave in a way that doesn’t match what it’s supposed to do. When the steps the program executes are logically correct in form, but the way they’re arranged or the conditions used are wrong, you get a logical error. This is exactly what happens when the code compiles and runs yet produces undesired output because the implemented logic doesn’t solve the problem as intended. Think about a function that checks if a number is prime but uses a faulty condition, like stopping the check after the first divisor found or testing only divisibility by 2. The program runs, but its result is incorrect for many inputs. That’s a logical error: the mistake lies in the reasoning or algorithm used, not in a single arithmetic calculation or precision issue. To contrast the others: an arithmetic error comes from a specific numeric operation going wrong, such as division by zero or an overflow, which is a problem with the calculation itself rather than the overall decision the program makes. A truncation error happens when you lose precision, like converting a real number to an integer or rounding during floating-point arithmetic—this is about accuracy, not the correctness of the general approach. Semantic error can be related to using language features incorrectly or misunderstanding how a construct should behave, but the effect described—producing outputs that don’t match the intended result due to flawed reasoning—fits best with a logical error.

The main idea is that a bug can make the program run but behave in a way that doesn’t match what it’s supposed to do. When the steps the program executes are logically correct in form, but the way they’re arranged or the conditions used are wrong, you get a logical error. This is exactly what happens when the code compiles and runs yet produces undesired output because the implemented logic doesn’t solve the problem as intended.

Think about a function that checks if a number is prime but uses a faulty condition, like stopping the check after the first divisor found or testing only divisibility by 2. The program runs, but its result is incorrect for many inputs. That’s a logical error: the mistake lies in the reasoning or algorithm used, not in a single arithmetic calculation or precision issue.

To contrast the others: an arithmetic error comes from a specific numeric operation going wrong, such as division by zero or an overflow, which is a problem with the calculation itself rather than the overall decision the program makes. A truncation error happens when you lose precision, like converting a real number to an integer or rounding during floating-point arithmetic—this is about accuracy, not the correctness of the general approach. Semantic error can be related to using language features incorrectly or misunderstanding how a construct should behave, but the effect described—producing outputs that don’t match the intended result due to flawed reasoning—fits best with a logical error.