/in/foo.c:1:1: warning: data definition has no type or storage class
 a=int(input("请输入学校需要购买几种图书："))
 ^
/in/foo.c:1:1: warning: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
/in/foo.c:1:3: error: expected expression before 'int'
 a=int(input("请输入学校需要购买几种图书："))
   ^~~