classes in java
public class HelloWorld {
public static void main(String[] args) {
class Number{
int number;
public boolean isPos(){
if(number > 0){
return true;
} else {
return false;
}
}
}
Number myNumber = new Number();
myNumber.number = 7;
if(myNumber.isPos()){
System.out.println(myNumber.number + " is positive!!!");
} else {
System.out.println(myNumber.number + " is not positive!!!");
}
}
}
public class HelloWorld {
public static void main(String[] args) {
// how to use class in java
class User{
int score;
// method that can be used outside the class
public boolean hasWon(){
if(score >= 100){
return true;
} else {
return false;
}
}
}
User dave = new User();
dave.score = 20;
System.out.println(dave.hasWon());
}
}
// this might help you understand how classes work
public class MathTest {
public static void main(String[] args) {
class MathAdd {
int num1;
int num2;
public int addNumbers() {
int addThemUp = num1 + num2;
return addThemUp;
}
}
MathAdd addition = new MathAdd(); // create a new instance of the class
// you can access variables from the class
addition.num1 = 10;
addition.num2 = 20;
// and use the method from the class to add them up
System.out.println(addition.addNumbers());
}
}
class Number {
int number;
// square numbers
public boolean isSquare(){
double squareRoot = Math.sqrt(number);
if(squareRoot == Math.floor(squareRoot))
{
return true;
} else {
return false;
}
}
// triangular numbers
public boolean isTriangular(){
int x = 1;
int triangularNumber = 1;
while(triangularNumber < number){
x++;
triangularNumber = triangularNumber + x;
}
if(triangularNumber == number){
return true;
} else {
return false;
}
}
}
// testing
Number myNumber = new Number();
myNumber.number = 16;
System.out.println(myNumber.isSquare());
Class is a blueprint or template which you can create as many objects as you
like. Object is a member or instance of a class.
Class is declared using class keyword, Object is created through
new keyword mainly. A class is a template for objects. A class defines
object properties including a valid range of values, and a default value.
A class also describes object behavior.
import java.lang.Math;
import java.util.Scanner;
public class HelloWorld {
public static void main(String[] args) {
class ResultNumberShape {
double number;
public boolean isSquare(double number) {
double result = Math.sqrt(number);
return ((result - Math.floor(result)) == 0);
}
}
ResultNumberShape checkNumber = new ResultNumberShape();
System.out.println("Enter any number:");
Scanner scanner = new Scanner(System.in);
double num = scanner.nextDouble();
scanner.close();
if (checkNumber.isSquare(num)) {
System.out.println(num + " is a sqaure number!");
} else {
System.out.println(num + " is not a square!");
}
}
}