Programming with Java

CHAPTER 3

JAVA LANGUAGE BASICS

It is said that the best way to learn swimming is to jump into the water right away. Similarly, the best way to learn a programming language is to start coding straight away. Let us start our study of Java programming in an informal way. Let us write a simple Java program and run it.

3.1 Introduction

In our first Java program, we will find the area of a circle with radius 5.

Problem: Write a program to find area of a circle with radius 5.

Solution: See Program 3.1.

 

PROGRAM 3.1 Area of a Circle

 //    first.java

 class first

  {

 public static void main( String args[] )

  {

   int r ;

   r = 5 ;

   System.out.println(3.14 * r * r);

  }

 }

If you run the program, you will get the following output.

 

Output

 78.5 ...