Introduction to Java Programming and Data Structures, Comprehensive Version (11th Edition)
Introduction to Java Programming and Data Structures, Comprehensive Version (11th Edition)
11th Edition
ISBN: 9780134670942
Author: Y. Daniel Liang
Publisher: PEARSON
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Chapter 6, Problem 6.1PE

(Math: pentagonal numbers) A pentagonal number is defined as n(3n − 1)/2 for n = 1, 2, ... , and so on. Therefore, the first few numbers are 1, 5, 12, 22, .... Write a method with the following header that returns a pentagonal number:

public static int getPentagonalNumber(int n)

For example, getPentagonal Number (1) returns 1 and getPentagonalNumber(2) returns 5. Write a test program that uses this method to display the first 100 pentagonal numbers with 10 numbers on each line. Use the %7d format to display each number.

Expert Solution & Answer
Check Mark
Program Plan Intro

Program Plan:

  • Declare the class “Penta”
  • Definition for main class
    • Use for loop to iterate the variable “j” equals to “100”.
    • Check whether “j” mod “10” equals to 0.
      • Call the method “getPentagonalNumber()”.
    • Otherwise, call the method “getPentagonalNumber()” concatenate with space.
  • Method definition for “getPentagonalNumber()”
    • Return “n * (3 * n - 1) / 2”.
Program Description Answer

Program to display first 100 pentagonal numbers with 10 numbers on each line using the method “getPentagonalNumber ()”

Explanation of Solution

Program:

//Definition for class "Penta"

public class Penta

{

//Definition for main class

public static void main(String[] args)

{

//For loop to iterate the variable

for (int j = 1; j <= 100; j++)

//Check whether the variable "j" mod 10 equals to "0"

if (j % 10 == 0)

//Call the method "getPentagonalNumber"

System.out.println(getPentagonalNumber(j));

else

//Call the method "getPentagonalNumber"

System.out.print(getPentagonalNumber(j) + " ");

}

//Method definition for "getPentagonalNumber"

public static int getPentagonalNumber(int n)

{

//Return the result

return n * (3 * n - 1) / 2;

}

}

Sample Output

1 5 12 22 35 51 70 92 117 145

176 210 247 287 330 376 425 477 532 590

651 715 782 852 925 1001 1080 1162 1247 1335

1426 1520 1617 1717 1820 1926 2035 2147 2262 2380

2501 2625 2752 2882 3015 3151 3290 3432 3577 3725

3876 4030 4187 4347 4510 4676 4845 5017 5192 5370

5551 5735 5922 6112 6305 6501 6700 6902 7107 7315

7526 7740 7957 8177 8400 8626 8855 9087 9322 9560

9801 10045 10292 10542 10795 11051 11310 11572 11837 12105

12376 12650 12927 13207 13490 13776 14065 14357 14652 14950

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Chapter 6 Solutions

Introduction to Java Programming and Data Structures, Comprehensive Version (11th Edition)

Ch. 6.5 - Prob. 6.5.1CPCh. 6.5 - Identify and correct the errors in the following...Ch. 6.5 - Prob. 6.5.3CPCh. 6.5 - Prob. 6.5.4CPCh. 6.6 - Prob. 6.6.1CPCh. 6.6 - Prob. 6.6.2CPCh. 6.7 - What is hexCharToDecimal ( B)) ? What is...Ch. 6.8 - What is method overloading? Is it permissible to...Ch. 6.8 - What is wrong in the following program? public...Ch. 6.8 - Given two method definitions, public static double...Ch. 6.9 - Prob. 6.9.1CPCh. 6.9 - What is the scope of a local variable?Ch. 6 - (Math: pentagonal numbers) A pentagonal number is...Ch. 6 - (Sum the digits in an integer) Write a method that...Ch. 6 - (Palindrome integer) Write the methods with the...Ch. 6 - (Display an integer reversed) Write a method with...Ch. 6 - (Sort three numbers) Write a method with the...Ch. 6 - (Display patterns) Write a method to display a...Ch. 6 - (Financial application: compute the future...Ch. 6 - (Conversions between Celsius and Fahrenheit) Write...Ch. 6 - Prob. 6.9PECh. 6 - (Use the isPrime Method) Listing 6.7,...Ch. 6 - (Financial application: compute commissions) Write...Ch. 6 - (Display characters) Write a method that prints...Ch. 6 - (Sum series) Write a method to compute the...Ch. 6 - (Estimate ) can be computed using the following...Ch. 6 - (Financial application: print a tax table) Listing...Ch. 6 - Prob. 6.16PECh. 6 - Sections 6.10 and 6.11 6.17 (Display matrix of 0s...Ch. 6 - (Check password) Some Websites impose certain...Ch. 6 - (Triangles) Implement the following two methods: /...Ch. 6 - (Count the letters in a string) Write a method...Ch. 6 - (Phone keypads) The international standard...Ch. 6 - (Math: approximate the square root) There are...Ch. 6 - (Occurrences of a specified character) Write a...Ch. 6 - (Display current date and time) Listing 2.7,...Ch. 6 - Prob. 6.25PECh. 6 - (Palindromic prime) A palindromic prime is a prime...Ch. 6 - (Emirp) An emirp (prime spelled backward) is a...Ch. 6 - (Mersenne prime) A prime number is called a...Ch. 6 - (Twin primes) Twin primes are a pair of prime...Ch. 6 - (Game: craps) Craps is a popular dice game played...Ch. 6 - (Financial: credit card number validation) Credit...Ch. 6 - (Game: chance of winning at craps) Revise...Ch. 6 - (Current date and time) Invoking System....Ch. 6 - (Print calendar) Programming Exercise 3.21 uses...Ch. 6 - (Geometry: area of a pentagon) The area of a...Ch. 6 - (Geometry: area of a regular polygon) A regular...Ch. 6 - (Format an integer) Write a method with the...Ch. 6 - (Generate random characters) Use the methods in...Ch. 6 - (Geomentry: point position) Programming Exercise...

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