foo.c:1:1: warning: data definition has no type or storage class
    1 | n=int(input("提供的餐品数量是"))
      | ^
foo.c:1:1: warning: type defaults to ‘int’ in declaration of ‘n’ [-Wimplicit-int]
foo.c:1:3: error: expected expression before ‘int’
    1 | n=int(input("提供的餐品数量是"))
      |   ^~~