Difficulty: Hard
Correct Answer: The program will print the output 6 6 12.
Explanation:
Introduction / Context:
This question highlights two advanced C++ concerns: (1) argument evaluation order is unspecified before C++17 (and unsequenced vs indeterminately sequenced rules have evolved), and (2) aliasing via int &y = x means both names refer to the same object. Many textbook compilers for such quizzes commonly evaluate left-to-right in practice, producing a particular observable result.
Given Data / Assumptions:
Concept / Approach:
A prevalent evaluation path (and the intended answer in classic MCQs) first applies ++y (making x=6, y=6), and then computes x + y using the updated values, giving 12. The first argument observes the updated x as 6. The function stores (a, b, c) accordingly and Display prints them.
Step-by-Step Solution:
Verification / Alternative check:
Different compilers or standards can yield different sequencing; however, competitive-programming/MCQ contexts typically expect the shown result. Using explicit temporaries or parentheses would remove ambiguity.
Why Other Options Are Wrong:
They assume older values (e.g., x=5) persist after ++y or mis-compute the sum.
Common Pitfalls:
Ignoring aliasing (x and y are the same) and relying on a guaranteed left-to-right evaluation across all standard versions.
Final Answer:
The program will print the output 6 6 12.
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