Assume that inputFile references a Scanner object that was used to open a file. Which of the following while loops shows the correct way to read data from the file until the end of the file is reached?
A) while (inputFile != null)
{ … }
B) while (!inputFile.EOF)
{ … }
C) while (inputFile.hasNext())
{ … }
D) while (inputFile.nextLine == " ")
{ … }

Question

Quizplus · Accepted Answer

The while loop while (inputFile.hasNext()) will iterate as long as there is a next token (or line, depending on the usage of the Scanner object) available in the inputFile. This is the correct and recommended way to read data from a file until the end of the file is reached. Option A is an infinite loop that will not terminate, as inputFile will never become null during file reading operations. Option B is not a valid method of checking for the end of file in Java, as there is no EOF property or method for Scanner objects. Option D is also incorrect, as the condition inputFile.nextLine == " " will only check if the next line in the file is a single space character, and will not by itself check if the end of the file has been reached.

Assume That InputFile References a Scanner Object That Was Used