Write a sequence of statements that create a file named "greeting" and write a single line consisting of "hello, world! " to that file. make sure that the line has been flushed to the file and that any system resources used during the course of running these statements have been released.

Which action is good business etiquette? a. switching your cell phone off before you enter a meeting b. keeping your cell phone on low volume before you enter a meeting c. setting a pleasant ring tone on your cell phone before you enter a meeting d. setting a standard ringtone on your cell phone before you enter a meeting

List a few alternative options and input and output over the standerd keyboard and monitor. explain their functioning in details.

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?