Spot the difference

What this C++ code-reading question tests

This is an easy C++ question that asks you to trace through a code snippet and predict its output. It is a warm-up exercise designed to check whether you are comfortable reading and mentally executing C++ syntax, including variable scope, type behavior, and standard library behavior.

Questions like this appear early in coding interviews to establish baseline competency. They reward careful attention to detail: off-by-one errors, implicit type conversions, pointer vs. value semantics, and the precise behavior of standard containers or operators often trip up candidates who skim rather than read. The skill being tested is not algorithmic insight but rather the ability to reason accurately about what code actually does, line by line.

• Variable scope and lifetime
• Type conversions and operator precedence
• Standard library container and function behavior
• Difference between declaration and initialization