Question

Create a Boolean function odd_number_digits(n) that returns True when a positive integer has an odd number of digits. (You may assume that I will not use a number greater than 1,000,000.) Then, use it to make a
function sum_odd_digits(n) that sums all the numbers from 0 to n that have an odd number of digits.

Answer 1

Answer:

Following are the code to this question:

import java.util.*;//import package for user input

public class Main//defining class main

{

   public static boolean odd_number_digits(int n)//defining boolean method odd_number_digits

   {

       if(n>0 && n%2!=0)//defining if block that check value is positive and odd number

       {

       return true;//return value true

       }

       else//defining else block

       {

           return false;//return false value

       }

   }

   public static void  sum_odd_digits(int n)//defining a method sum_odd_digits

   {

       int sum=0,i;//defining integer variable

       for(i=0;i<=n;i++)//defining for loop

       {

           if(i%2!=0)//defining if block for odd number

           {

               sum=sum+i;//add odd number

           }

       }

      System.out.print(sum);//use print method to print sum value

   }

public static void main(String[] args) //defining main method

   {

       Scanner ox=new Scanner(System.in);//creating Scanner object

       int n= ox.nextInt();//defining integer variable for input value

       System.out.print(odd_number_digits(n)+ "\n");//use print method to call method

       System.out.println("Sum of odd numbers: ");//print message

       sum_odd_digits(n);//calling method

   }

}

Output:

please find the attachment.

Explanation:

In the above code, two methods "odd_number_digits and sum_odd_digits" are defined in which the first method return type is boolean because it will true or false value, and the second method returns the sum of odd numbers.

In the "odd_number_digits" method,  an integer variable passes as an argument and inside the method, if block is used that check value is a positive and odd number then it will return a true value.

In the "sum_odd_digits" method, it accepts an integer parameter "n", and define integer variable "sum" inside the method, which uses the for loop, inside the loop if block is used that counts odd numbers and adds its in sum and print its value.