# ECS2301 Software Engineering and Project – Lesson 4

• Simple Java code snippets

## Calculating circumference of a circle

``````package circumference;

import java.util.Scanner;

/**
* Uses Java Math library
* @author azmeer
*/
public class Circumference {

public static void main(String[] args) {
System.out.println("Calculate the circumference of a circle - with user input");
Scanner in = new Scanner(System.in);
int r;
double c;

r = in.nextInt();

c = 2 * Math.PI  * r;
System.out.println("pi=" + Math.PI);
System.out.println("radius=" + r + " circumference=" + c);
}
}
``````

## Odd/Even detector with modulo operator

``````import java.util.Scanner;

/**
* Using modulo operator
* @author azmeer
*/
public class OddEven {

public static void main(String[] args) {
int n, x;
System.out.println("Odd/Even detector");

Scanner in = new Scanner(System.in);
n = in.nextInt();

x = n % 2;

if (x == 0) {
System.out.println(n + " is an even number");
} else {
System.out.println(n + " is an odd number");
}

}
}``````

## Age calculator

If the age is less than 18, then the person is a child

``````import java.util.Scanner;

/**
* Calculate age with given year of birth value
*
* @author azmeer
*/
public class CalcAge {

public static void main(String[] args) {
System.out.println("Age Calculator");

Scanner in = new Scanner(System.in);
int age, yob;

System.out.print("What is your year of birth? ");
yob = in.nextInt();
age = 2023 - yob;

System.out.println("You are " + age + " years old");

if (age < 18) {
System.out.println("You are a child");
} else {