ELEMENTARY PROGRAMMING - Introduction to Java Programming - page 38

T ABLE 2.1 Methods for Scanner Objects

Method Description

reads an integer of the byte type.

nextByte()

reads an integer of the short type.

nextShort()

reads an integer of the int type.

nextInt()

reads an integer of the long type.

nextLong()

reads a number of the float type.

nextFloat()

reads a number of the double type.

nextDouble()

reads a string that ends before a whitespace character.

next()

reads a line of text (i.e., a string ending with the Enter key pressed).

nextLine()

8 // Prompt the user to enter a radius
9 System.out.print( "Enter a number for radius: " );
10

read a double

double radius = input.nextDouble();

11
12 // Compute area

13 double area = radius * radius * 3.14159;

14
15 // Display results
16 System.out.println( "The area for the circle of radius " +
17 radius + " is " + area);
18 }
19 }

Enter a number for radius:
The area for the circle of radius 2.5 is 19.6349375

2.5

Enter a number for radius:
The area for the circle of radius 23.0 is 1661.90111

23

The Scanner class is in the java.util package. It is imported in line 1. Line 6 creates a
Scanner object.
The statement in line 9 displays a message to prompt the user for input.

System.out. print ( "Enter a number for radius: " );

The print method is identical to the println method except that println moves to the
beginning of the next line after displaying the string, but print does not advance to the next
line when completed.
The statement in line 10 reads input from the keyboard.

print vs. println

double radius = input.nextDouble();

After the user enters a number and presses the Enter key, the program reads the number
and assigns it to radius .