A Level Computer Science OCR Practice Exam

What is the role of the XOR logical operator?

1. Returns TRUE if both values are the same

2. Returns TRUE if both values are different

3. Returns FALSE if at least one is TRUE

4. Returns TRUE only if both values are FALSE

The correct answer is: Returns TRUE if both values are different

The XOR (exclusive OR) logical operator plays a specific role in evaluating two boolean values. It returns TRUE if and only if one of the values is TRUE and the other is FALSE; in other words, it requires the two values to be different. This characteristic makes it particularly useful in situations where you want to confirm that exactly one condition is met without satisfying both conditions simultaneously. For example, if you apply XOR to the boolean values TRUE and FALSE, it will result in TRUE because they are indeed different. Conversely, applying XOR to TRUE and TRUE or FALSE and FALSE would yield FALSE, as both values in each case are the same. Thus, the definition of XOR aligns directly with the assertion that it returns TRUE if both values are different. This function is commonly used in programming and digital logic design, particularly in the fields of cryptography and error detection.