CONTROL STRUCTURES II: REPETITION - Java Programming: From Problem Analysis to Program Design - page 267

Recall that the following statement creates the Scanner object console and initializes it
to the standard input device:

static Scanner console = new Scanner(System.in); //Line 1

This statement is equivalent to the following statements:

static Scanner console; //Line 2
console = new Scanner(System.in); //Line 3
The statement in Line 2 declares console to be the Scanner variable; the statement in
Line 3 initializes console to the standard input device. On the other hand, the statement
in Line 1 both declares and initializes the Scanner variable console .
The method hasNext ,ofthe class Scanner , returns true if there is an input in
the input stream, otherwise it returns false . In other words, the expression
console.hasNext() evaluates to true if there is an input in the input stream; otherwise,
it

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returns false . Therefore, the expression console.hasNext() acts as the loop

condition.
It now follows that a general form of the EOF-controlled while loop that uses the
Scanner object console to input data is of the following form (we assume that console
has been created and initialized using either the statement in Line 1 or the statements in
Lines 2 and 3):

while (console.hasNext())
{

//Get the next input (token) and store it in an
//appropriate variable
//Process the data

}

In the Windows console environment, the end-of-file marker is entered using Ctrl+z .
(Hold the Ctrl key and press z .) In the UNIX environment, the end-of-file marker is
entered using Ctrl+d . (Hold the Ctrl key and press d .)

Suppose that inFile is a Scanner object initialized to the input file. In this case, the
EOF-controlled while loop takes the following form:

while (inFile.hasNext())
{

//Get the next input (token) and store it in an
//appropriate variable
//Process the data

}