C#.NET — Evaluate truth, short-circuiting, and condition outcomes for: if (age > 18 && no < 11) a = 25;
-
A1, 3
-
B2, 5
-
C1, 4, 5
-
D3, 4, 5
-
ENone of these
Answer
Correct Answer: 1, 4, 5
Explanation
Introduction / Context:This tests understanding of the logical AND operator && in C#, including short-circuit evaluation and the exact condition needed for assignment to execute.
Given Data / Assumptions:
- Statement: if (age > 18 && no < 11) a = 25;
- Options list claims about evaluation order and when a = 25 runs.
Concept / Approach:In C#, && is a short-circuiting operator. The right-hand condition is evaluated only if the left-hand condition is true. The if body executes only if both subconditions evaluate to true.
Step-by-Step Solution:
Analyze statement 1: "no < 11 is evaluated only if age > 18 is True." Correct due to short-circuiting. Statement 2: "a = 25 executes if any one condition is True." Incorrect; both must be true. Statement 3: "no < 11 is evaluated only if age > 18 is False." Incorrect; it is evaluated only if the left side is True. Statement 4: "a = 25 executes if both conditions are True." Correct. Statement 5: "&& is short-circuiting." Correct.Verification / Alternative check:Truth table for && confirms that the right operand evaluates only when the left operand is true and the overall result is true only when both are true.
Why Other Options Are Wrong:
- A: includes 3 which is false.
- B: includes 2 which is false.
- D: includes 3 which is false.
- E: incorrect because a correct combination exists.
Common Pitfalls:Confusing && with ||, or assuming both sides always evaluate. With &&, the second operand can be skipped.
Final Answer:1, 4, 5