Question

Write a complete Java program, including comments in both the main program and in each method, which will do the following:

0. The main program starts by calling a method named introduction which prints out a description of what the program will do. This method is called just once.

     This method is not sent any parameters, and it does not return a value. The method should print your name. Then it prints several lines of output explaining what the program does (it should also say how to end the set of data—see step 4).

1. Then the main program asks the user to type in an integer value which the main program calls n; n could be positive, negative, or zero (see step 4). The main program prints the number n after it is read in. Use a negative value to end.

2. The main program calls a method named isiteven, sending it the integer value n as a parameter. The method determines whether or not n is even, sending the answer back to main. (Hint: if n is even, the remainder when n is divided by 2 is 0; this works for all even numbers, including 0.) You may return an integer (like 0 or 1) to represent even or odd, or return a character (like ‘e’ or ‘o’), or a boolean.

The main program prints the answer returned together with a message. For example, if you send 6, the method determines it is even, and the main program prints that 6 is an even number.

3a. If n is even, the main program calls a method named sumEvenSquares, sending n to the method as a parameter. The method computes the sum of the first n even squares (see below). The method returns this sum to the main program. Then the main program prints a message giving n and the sum of the first n even squares.

For example, if you send 4, then the sum of the first 4 even squares is 2*2 + 4*4 + 6*6 + 8*8 = 4+16+36+64 = 120.

Note the method computes the sum of the first n even squares- this will be: 2*2 + 4*4 + 6*6 + ... + (2n)*(2n), where n is the parameter value sent to the method. DO NOT use any other formula for calculating this value; use the sum of series.

b. However, if n is odd, the main program calls a method named sumOddNumbers, sending it n. The method computes the sum of the first n odd numbers (NOT n odd squares - see below). The method returns this sum to the main program. Then the main program prints a message giving n and the sum of the first n odd numbers.

For example, if you send 3, then the sum of the first 3 odd numbers is 1 + 3 + 5 = 9. For n=5, it is 1+3+5+7+9 = 25, etc. (Although this value will be equal to n squared, calculate it as a series; don’t just find n squared.)

Note the method computes the sum of the first n odd numbers- this will be: 1 + 3 + 5 + ... + (2n-1), where n is the parameter value sent to the method.

In either case, the main program calls one of two methods to compute a sum of terms, then prints the method's answer.

4. After calling a method to compute the appropriate sum and printing the result, the main program will skip a few lines and go back to step 1 (not step 0).   At step 1, if the user types in a negative value, the program will go to step 5.

5. At the end, print how many data values were entered and processed. (Make sure that this number is at least 8.)

DATA: Type in a total of at least 8 data values. Have at least four even numbers (make sure 0 is one of the even numbers) and four odd numbers; intersperse the values: odd, then 2 evens, then odd, etc. Have one value of each type that is between 10 and 20 (and the rest smaller).

     You will be judged on the quality of your data.

STYLE: Be sure that each method has a good comment explaining two things: exactly what parameter(s) the method will receive, and exactly what the method will do (and if it returns an answer or prints). Mention parameters by name in the comment.

OUTPUT: Send output to an external file. You will need to pass it as a parameter.

Here is some sample output (ignoring the introduction):

the original integer is 5

5 is an odd number

the sum of the first 5 odd numbers is 25

the original integer is 4

4 is an even number

the sum of the first 4 even numbers is 120

OPTIONAL: If the user enters a negative value, say this is no good, ask the user to type in a new value that is good (greater than or equal to 0). The program continues until the user enters a special value (not just any negative value) that signals the end.

Answer 1

import java.util.Scanner;
public class Main{
        // this method prints some
        // introductory message
        public void introduction(){
                System.out.println("\nWelcome to Program");
                System.out.println("My name is XXX YYY");
                System.out.print("This method takes an integer from the user."); 
                System.out.print("If the input is even it prints the square sum of first n even numbers. ");
                System.out.println("If the input is odd it prints the sum of first n odd numbers.\n");
                
        }
        // this function checks if a number n is 
        // even or odd. 
        // If even then return true
        // else return false
        public boolean isiteven(int n){
                if(n%2==1)
                        return false;
                return true;
        }
        // this methods returns  sum of 
        // first n odd integers
        public int sumOddNumbers(int n){
                int sum=0, i;
                // run from 1 to 2*n with 
                // increment value=2
                for(i=1; i<=2*n;i+=2)
                        sum+=i;
                // return result
                return sum;
        }
        
        // this methods returns square sum of 
        // first n even integer
        public int sumEvenSquares(int n){
                int sum=0, i;
                // run from 2 to 2*n with 
                // increment value=2
                for(i=2; i<=2*n;i+=2)
                        sum+=i*i;
                // return result
                return sum;
        }
        
        public static void main(String[] args){
                // declare variables
                int n, result,data_count=0, process_count=0;
                
                // declare scenner class object
                Scanner sc=new Scanner(System.in);
                
                //declare object of class
                Main obj=new Main();
                
                //call inroduction()
                // no parameter is passed
                // no return value
                obj.introduction();
                
                while(true){
                        //take input of n
                        System.out.print("Enter a integer: ");
                        n=sc.nextInt();
                        data_count++;
                        System.out.println("The original integer is: "+n);
                        // if negative then break the loop
                        if(n<0)
                                break;
                        // call isiteven()
                        // input value n is passed
                        // if n is even it returns true
                        // else it will return false
                        boolean k=obj.isiteven(n);
                        if(k){
                                System.out.println(n+" is an even number");
                                // call sumEvenSquares()
                                // input value n is passed
                                // it will return square sum of first n 
                                // even numbers
                                result=obj.sumEvenSquares(n);
                                System.out.println("The square sum of first "+n+" even integers is: "+result);

                        }
                        else{
                                System.out.println(n+" is an odd number");
                                // call sumOddNumbers()
                                // input value n is passed
                                // it will return sum of first n 
                                // odd numbers
                                result=obj.sumOddNumbers(n);
                                System.out.println("The sum of first "+n+" odd integers is: "+result);
                        }
                        process_count++;
                }
                
                System.out.println("Total data value entered: "+data_count);
                System.out.println("Total data processed: "+process_count);
        }
}

___________________________________________________________________

Welcome to Program
My name is XXX YYY
This method takes an integer from the user.If the input is even it prints the sq
uare sum of first n even numbers. If the input is odd it prints the sum of first
 n odd numbers.

Enter a integer: 11
The original integer is: 11
11 is an odd number
The sum of first 11 odd integers is: 121
Enter a integer: 12
The original integer is: 12
12 is an even number
The square sum of first 12 even integers is: 2600
Enter a integer: 5
The original integer is: 5
5 is an odd number
The sum of first 5 odd integers is: 25
Enter a integer: 2
The original integer is: 2
2 is an even number
The square sum of first 2 even integers is: 20
Enter a integer: 7
The original integer is: 7
7 is an odd number
The sum of first 7 odd integers is: 49
Enter a integer: 5
The original integer is: 5
5 is an odd number
The sum of first 5 odd integers is: 25
Enter a integer: 8
The original integer is: 8
8 is an even number
The square sum of first 8 even integers is: 816
Enter a integer: 4
The original integer is: 4
4 is an even number
The square sum of first 4 even integers is: 120
Enter a integer: -1
The original integer is: -1
Total data value entered: 9
Total data processed: 8

___________________________________________________________________

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