PaycomOA #20
Q20. Declaration vs Definition
估计简单概念题评测数据准备中，可先阅读题面
考点（AI 标注）模拟/实现
Which is true about a declaration and a definition of a variable?
- Both can occur multiple times, but a declaration must occur first.
- There is no difference between them.
- A definition occurs once, but a declaration may occur many times. <-
- A declaration occurs once, but a definition may occur many times.
- Both can occur multiple times, but a definition must occur first.