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Polite.java
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Polite.java
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import java.util.InputMismatchException;
import java.util.Scanner;
public class Polite {
// This class returns the nth element of the Polite numbers where n is a positive integer input by the user
// The polite numbers are the sequence of natural numbers that are not powers of 2
public static void main(String[] args) {
System.out.println("The Nth element of the Polite numbers is " + polite());
}
public static int userInput() {
Scanner scanner = new Scanner(System.in);
int n = -1;
// The loop is used to check if the number input by the user is a positive integer or zero
while(true) {
// Keeps track if exception was encountered
boolean exception = false;
try {
System.out.print("Enter a number: ");
// Prompt the user to enter a number
n = scanner.nextInt();
}
// Catches an exception if the user input is not an integer
catch (InputMismatchException e) {
System.out.println("Invalid input. Please enter an integer input.\n");
// Discards the invalid token inputed to avoid an infinite loop
scanner.next();
// True if exception was encountered
exception = true;
}
if(n > -1) {
scanner.close();
return n;
}
// Else a negative integer was inputed
else if(exception == false) {
System.out.println("Invalid number. Please enter a positive number.\n");
}
}
}
public static long polite() {
int i = 1;
int count = 0;
int n = userInput();
// Count the first n natural numbers that are not powers of 2, which will return the nth polite number
while (count<=n) {
// Check if a number is not power of 2
if((Math.log(i))/(Math.log(2)) != Math.round((Math.log(i))/(Math.log(2)))) {
// Count will not increment if the number is a power of 2
count++;
}
i++;
}
return(i-1);
}
}