Summing integer collections

What this C++ language-knowledge question tests

This is a medium-difficulty C++ question that asks you to trace through a code snippet and predict its output. It probes your understanding of how the language handles types, operations, and standard library containers in a realistic context.

To answer correctly, you need to follow the logic carefully, pay attention to data types and their conversions, and understand how standard library functions behave. These questions are common in technical interviews because they reveal whether you code with precision or rely on guesswork—a crucial distinction when milliseconds and correctness matter.

• Type inference and implicit conversions
• Standard library container behaviour
• Operator semantics and evaluation order