Getting Started - Java - page 6

Display 1.1 A Sample Java Program

Name of class
(program)

1 public class FirstProgram
2{
3 public static void main(String[] args)
4 {
5 System.out.println("Hello reader.");
6 System.out.println("Welcome to Java.");

The main method

7 System.out.println("Let's demonstrate a simple calculation.");
8 int answer;
9 answer = 2 + 2;
10 System.out.println("2 plus 2 is " + answer);
11 }
12 }

Sample Dialogue
Hello reader.
Welcome to Java.
Let's demonstrate a simple calculation.
2 plus 2 is 4

The next two lines, shown in what follows, are the first actions the program performs:

println System.out.println("Hello reader.");

System.out.println("Welcome to Java.");

. Each one causes the quoted
string given within the parentheses to be output to the screen. For example, consider

Each of these lines begins with

System.out.println

System.out.println("Hello reader.");

This causes the line

Hello reader.

to be written to the screen. The output produced by the next line that begins with

will go on the following line. Thus, these two lines cause the fol-

System.out.println

lowing output:

Hello reader.
Welcome to Java.

are a way of saying “output what
is shown in parentheses,” and the details of why the instruction is written this way
need not concern us yet. However, we can tell you a little about what is going on here.

These lines that begin with

System.out.
println

System.out.println