Question

The program Nadha Skolar wrote is supposed to read an integer value supplied by the user that should be between 1-30. Using the value supplied (let's call it n), three different summation formulas should be calculated using three different methods. Nadha Skolar was supposed to write a program to read the user's input, ensure that it is a value between 1-30 and then call the appropriate methods to calculate the summations and print the results:

• summationN() - Calculates and returns the summation of the first n integers. This should be calculated using n(n+1)/2
• sumofOddN() - Calculates and returns the summation of the first n odd integers. This should be calculated using n²
• sumOfSquaresN() - Calculates and returns the sum of squares of the first n integers ∑i² from 1 to n. This should be calculated using n(n+1)(2n+1)/6

Sample Runs:

Run #1 (bad value for n):

Enter a number between 1-30 for the value of n: 0 <--- user enters the number for n
Program cannot continue. n must be a value 1-30.  <--- use a println

Run #2 (bad value for n):

Enter a number between 1-30 for the value of n: 31  <--- user enters the number for n
Program cannot continue. n must be a value 1-30. <--- use a println

Run #3:

Enter a number between 1-30 for the value of n: 3  <--- user enters the value for n

The summation of the first n numbers is: 6
The summation of the n odd numbers is: 9
The summation of n numbers squared is: 14 <--- use a println

Tips:

1. Test your program in intelliJ before copying it back to zyBooks.
2. When the program is working correctly, copy the code from intelliJ back to zyBooks and submit for grading.
3. Important: You may NOT erase and re-write the entire program or an entire method. Your job is to fix Nadha's thinking and programming.

import java.util.*;

/* Name: NadhaSkolar Solution

public class NadhaStrikesAgain { //my best work yet! I have just learned about methods!
public static void main(String[] args) {

//get the value for n
Scanner scnr = new Scanner(System.in);
int n = getN();

//ensure n is usable
if ((n <= 0) && (n > 30)){
System.out.println("Program cannot continue. n must be a value 1-30.");
}

int sum = summationN(n);
int sumodd = sumofOddN(sum);
int sumSquares = sumOfSquaresN(n);

displayResults(sumodd, sum, sumSquares); //print them out
}
}

// ************************************************
// DESCRIPTION - getN() - prompts for n and returns value to main
// ************************************************
public static void getN(Scanner scnr) {
//prompt for a number,
System.out.print("Enter a number between 1-30 for the value of n: ");
int n = scnr.nextInt();
return n;
}

// ************************************************
// DESCRIPTION - addOdd() computes summation of first "num" odd numbers using the formula n^2
// ************************************************
public static double sumofOddN(int num) {
return(num^2);
}

// ************************************************
// DESCRIPTION - summation() - computes and returns the summation of i from to N
// ************************************************
public static int summationN(int num) {
return(num * num + 1 / 2);
}

// ************************************************
// DESCRIPTION - sumOfSquares() - computes and returns the sum of squares of first "num" numbers
// ************************************************
public static int sumOfSquaresN(int n) {
return((num * (num + 1) * (2 * num + 1) / 6));
}

// ************************************************
// DESCRIPTION - displayResults() - displays the various summations
// ************************************************
public static void displayResults(int sum, int oddSum, int sumSquares) {
System.out.println();
System.out.println("The summation of the first n numbers is: " + sum);
System.out.println("The summation of the n odd numbers is: " + oddSum);
System.out.println("The summation of n numbers squared is: " + sumSquares);
}
}
}

Answer 1

Dear Student ,

As per the requirement submitted above , kindly find the below solution.

Here a new java program with name "NadhaStrikesAgain.java" is created, which contains following code.

NadhaStrikesAgain.java :

import java.util.*;//import package
/* Name: NadhaSkolar Solution
*/
//java class
public class NadhaStrikesAgain {
//my best work yet! I have just learned about methods!
//entry point , main method
   public static void main(String[] args) {
//get the value for n, object of scanner class
       Scanner scnr = new Scanner(System.in);
       int n = getN(scnr);
       //ensure n is usable
       if ((n <= 0) || (n > 30)) {
           System.out.println("Program cannot continue. n must be a value 1-30.");
       }
       else
       {
       int sum = summationN(n);//call method to get the sum
       int sumodd = sumofOddN(n);//call method to sum the odd numbers
       int sumSquares = sumOfSquaresN(n);//call the method to square the sum
       displayResults(sum,sumodd, sumSquares); // print them out
       }
   }

// ************************************************
// DESCRIPTION - getN() - prompts for n and returns value to main
// ************************************************
   public static int getN(Scanner scnr) {
       //prompt for a number,
       System.out.print("Enter a number between 1-30 for the value of n: ");
       int n = scnr.nextInt();//read input
       return n;//return n
   }

// ************************************************
// DESCRIPTION - addOdd() computes summation of first "num" odd numbers using the formula n^2
// ************************************************
   public static int sumofOddN(int num) {
       return (num*num);
   }

// ************************************************
// DESCRIPTION - summation() - computes and returns the summation of i from to N
// ************************************************
   public static int summationN(int num) {
       return num * (num + 1)/ 2;//return sum
   }

// ************************************************
// DESCRIPTION - sumOfSquares() - computes and returns the sum of squares of first "num" numbers
// ************************************************
   public static int sumOfSquaresN(int num) {
       return ((num * (num + 1) * (2 * num + 1) / 6));//return sum of squares
   }

// ************************************************
// DESCRIPTION - displayResults() - displays the various summations
// ************************************************
   public static void displayResults(int sum, int oddSum, int sumSquares) {
       System.out.println();
       System.out.println("The summation of the first n numbers is: " + sum);
       System.out.println("The summation of the n odd numbers is: " + oddSum);
       System.out.println("The summation of n numbers squared is: " + sumSquares);
   }

}

======================================================

Output : Compile and Run NadhaStrikesAgain.java to get the screen as shown below

Screen 1 :NadhaStrikesAgain.java ,Run #1 (bad value for n)

Screen 2 :NadhaStrikesAgain.java ,Run #2 (bad value for n)

Screen 3:Run #3

NOTE : PLEASE FEEL FREE TO PROVIDE FEEDBACK ABOUT THE SOLUTION.