Base 70里的第32题! 求解答

feng_2long

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收藏 2015-11-19

悬赏 2 个论坛币未解决

32.Consider the following data step:

data WORK.NEW;
set WORK.OLD;
Count+1;
run;

The variable Count is created using a sum statement. Which statement regarding this variable is true?
   A. It is assigned a value 0 when the data step begins execution.
   B. It is assigned a value of missing when the data step begins execution.
   C. It is assigned a value 0 at compile time.
   D. It is assigned a value of missing at compile time.

为什么答案是C ？？？？？？？

据我所知，compile阶段只是检查语句是否错误而已，并没有进行赋值的。只有在execution的阶段才开始赋值的吧？？？