Write a program to print the sum of negative numbers, sum of positive even numbers and the sum of positive odd numbers from a list of numbers (N) entered by the user. The list terminates when the user enters a zero.

Program to print the sum of negative numbers, sum of positive even numbers and the sum of positive odd numbers from a list of numbers (N) entered by the user. The list terminates when the user enters a zero in Java.

package com.hubberspot.java.example;

import java.util.Scanner;

public class SumArray {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int [] numbers = new int[0];

        int number;
        String nextLine;
        do {
            System.out.print("Enter the number : ");
            number = scanner.nextInt();
            nextLine = scanner.nextLine();

            if(number != 0) {
                numbers = add(numbers, number);
            }

        } while(number != 0);

        int negativeSum = 0; 
        int oddSum = 0; 
        int evenSum = 0;

        for(int i = 0; i < numbers.length; i++ )
        {
            if( numbers[i] < 0 )
            {
                negativeSum = negativeSum + numbers[i];
            }
            else if( numbers[i] % 2 == 0 )
            {
                evenSum = evenSum + numbers[i];
            }
            else
            {
                oddSum = oddSum + numbers[i];
            }
        }
        System.out.println( "Sum of negative numbers : " + negativeSum );
        System.out.println( "Sum of positive even numbers: " + evenSum );
        System.out.println( "Sum of positive odd numbers: " + oddSum );

    }

    private static int[] add(int[] numbers, int number) {

        int[] tempArray = new int[numbers.length + 1];

        for(int i = 0; i < numbers.length; i++) {
            tempArray[i] = numbers[i];
        }

        tempArray[tempArray.length - 1] = number;
        return tempArray;

    }

}

Output of the program : 

 

Write a Java program to print Padovan Sequence.

Program to implement Padovan sequence in Java.

The Padovan Sequence starts with three 1's and after that moves on with a function as : f(x) = f(x-2)+ f(x-3).

package com.hubberspot.java.sequences;

import java.util.Scanner;

public class Padovan {

    public static void main(String[] args) {
        
        int firstNumber = 1;
        int secondNumber = 1;
        int thirdNumber = 1;
                
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("Enter the number of terms for Padovan sequence : ");
        
        int noOfTerms = scanner.nextInt();
        int nextNumber;
        
        System.out.print( firstNumber + " " + secondNumber + " " + thirdNumber);
        
        for(int i = 1; i <= noOfTerms - 3; i++) { 
            
            nextNumber = secondNumber + firstNumber;
            System.out.print(" " + nextNumber);
            firstNumber = secondNumber;
            secondNumber = thirdNumber;
            thirdNumber = nextNumber;
            
        }        


    }

}

Output of the program : 

 

Write a Java program to print Jacobsthal Sequence.

Program to implement Jacobsthal sequence in Java.

The Jacobsthal sequence starts with numbers 0 and 1. After that each successive number is sum of previous number plus twice the number previous to previous number.

package com.hubberspot.java.sequences;

import java.util.Scanner;

public class Jacobsthal {

    public static void main(String[] args) {
       
        int firstNumber = 0;
        int secondNumber = 1;
                
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("Enter the number of terms for Jacobsthal sequence : ");
        
        int noOfTerms = scanner.nextInt();
        int nextNumber;
        
        System.out.print( firstNumber + " " + secondNumber);
        
        for(int i = 1; i <= noOfTerms - 2; i++) { 
            
            nextNumber = secondNumber + 2 * firstNumber;
            System.out.print(" " + nextNumber);
            firstNumber = secondNumber;
            secondNumber = nextNumber;
            
        }        

    }

}

Output of the program :