Question

1. Write a program to compute the product of two positive integers by repeated addition.

Note: You are not allowed to use either multiplication or division operator.

Understanding the Meaning of Multiplication:

Multiplication of whole numbers can be thought of as repeated addition.

// not allowed to use multiplication or division operator

For example, suppose that a parking lot has 6 rows of parking spaces with 8 spaces in each row. How many parking spaces are in the lot?

rows

To get total we add 8 six times,

8+8+8+8+8+8=48 or we can use a shortcut: 6 rows of 8 , which equal to 8.

This is multiplication, a shortcut for repeated addition.

When numbers are large, multiplication is easier than addition.

// Multiplication could be done by   reapeated Addition

package forinfinity;

import java.util.Scanner;

public class Main

{

public static void main(String[] args)

{

                        int a, b, i, product ;

                        

// Create a Scanner object for keyboard input.

                         Scanner keyboard = new Scanner(System.in);

                        

System.out.print("Enter the values of a and b: ");

                        a= keyboard.nextInt();//

                        b= keyboard.nextInt();//

                        i=0;

                        product=0;

                        while (i

                         {

                                     i=i +1;

                                    product=product + b;

                         }

                        System.out.print("The product is:" + product);       

            }

}

The Question I need help in is using the previous concept:

Write a JAVA application that determines volume of a cylinder by repeated addition.

You are not allowed to use either multiplication or division operator.

Use the formula

V = π r^2 L

Where V is the volume of the cylinder

r is the radius of the cylinder (user input)

l is the length of the cylinder (user input)

Answer 1

import java.util.*;

public class Main
{
   public static void main(String[] args) {
   Scanner keyboard=new Scanner(System.in);
       System.out.println("Enter radius");
       int r,l;
       r=keyboard.nextInt();
       System.out.println("Enter length");//read input from user
       l=keyboard.nextInt();
       int i=0,temp=0;
       while(i<r){
       temp=temp+r;//to calculate r^2 value
       i++;
       }
       i=0;
       int temp1=0;
       while(i<l){
       i++;
       temp1=temp+temp1;//calculate h*(r^2)
       }
       //pi value can be treated as 22/7.
       //So we multiply by 22 and divide the result by 7 to get the volume.
       i=0;
       temp=0;
       while(i<22){
       i++;
       temp=temp+temp1;//calculating 22*h*(r^2)
       }
       double quotient = 0,dividend=temp,divisor=7;
while (dividend >= divisor)
{
dividend -= divisor; //calculating 22*h*(r^2)/7.
++quotient;
}
System.out.println("The volume is:");
System.out.println(quotient);
   }
}

Screenshots:

Enter radius 9 Enter length 3 The volume is: 763.0 ..Program finished with exit code 0