Download Tell Me More About Scanners

Tell me more about Scanners

Scanner is part of the java.util standard library.

An import statement indicates that the software needs to make use of
a library.

Import statements occur immediately before the class definition.

The statement
import java.util.*;
provides access to the entire java.util library.

Scanner is a class, but it is not a program. What we can get from it are
Scanner objects.

A Scanner object can be directed to get information from an input
source.

Java supplies the new operator to get a new object.

The act of setting up a new object is called construction.

The method that performs setting up is called a constructor.

A Scanner constructor can be given a parameter to specify the input
source.

Java provides System.in as the input counterpart to System.out; that
is, System.in is the Java representation of a user's keyboard. When
System.in is specified to be the input source for a Scanner, a program
can use the Scanner to process user input.

The expression
new Scanner( System.in )
produces and constructs a new Scanner object that can read what the
user enters.

The statement
Scanner stdin = new Scanner( System.in )
defines and initializes a Scanner variable named stdin. With the
variable, a program can send messages to its object to read the next
number, string, line of text, or logical value.

Every Scanner object has a method nextInt() for reading the next
input as an integer value.

Every Scanner object has a method nextDouble() for reading the next
input as a decimal value.

Every Scanner object has a method nextBoolean() for reading the next
input as a logical value.

Every Scanner object has a method next() for reading the next input
as a string.

Every Scanner object has a method nextLine() for reading the rest of
the current line of input as a string.