题目
https://blog.csdn.net/rentao8000/article/details/7937484?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522166556143416782428654636%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=166556143416782428654636&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~blog~sobaiduend~default-1-7937484-null-null.nonecase&utm_term=c%E8%AF%AD%E8%A8%80%E8%B6%85%E7%BA%A7%E7%BB%8F%E5%85%B8400%E9%81%93%E9%A2%98%E7%9B%AE&spm=1018.2226.3001.4450
6、C（答案错）
double也是有效类型
7、
C语言中两个*是什么意思?比如int**p
