Can someone help me with these problems? 1.A pentagonal number is defined as n*(
ID: 674399 • Letter: C
Question
Can someone help me with these problems? 1.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 void getPentagonalNumber (int n)
Write a test program that calls this method to display the first 50 pentagonal numbers with 5 numbers on each line. Use printf to ensure the numbers are aligned to the right.
2.Write a class that contains the following two methods:
public static double celsiusToFahrenheit (double celsius)
public static double fahrenheittoCelsius (double Fahrenheit)
The formula for the conversion is: fahrenheit = (9.0 / 5) * celsius + 32 celsius = (5.0 / 9) * (Fahrenheit – 32)
Write a test program that invokes these methods
3.Write a method that counts the number of letters in a string using the following header:
public static int countLetter tString s)
public static int countDigits (String s)
Write a method that counts the number of digits in a string using the following header: Write a test program that prompts the user to enter a string and displays the number of letters and the number of digits in the string. Please help I am lost
Explanation / Answer
public class PentagonalNumber {
public static void main(String[] args) {
for (int i = 1; i <= 100; i++) {
//System.out.print(getPentagonalNumber(i) + (i %10 == 0? System.getProperty("line.separator") : " ")); //advanced ;D
System.out.print(getPentagonalNumber(i));
if (i % 10 == 0) {
System.out.println();
} else {
System.out.print(" ");
}
}
}
public static int getPentagonalNumber(int n) {
return (3 * n * n - n) / 2;
}
}
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