/**

* Write a program called Tribonacci to display the first 20 Tribonacci numbers

* F(n), where F(n) = F(n–1) + F(n–2) + F(n–3) and T(1) = T(2) = 1, and T(3)=2.

* Also compute their average.

*/

package javaexercises.flowcontrol;

/**

*

* @author User

*/

public class Tribonacci {

public static void main(String[] args) {

Tribonacci aTribonacci = new Tribonacci();

aTribonacci.printTribonacciAndAverage(20);

}

public void printTribonacciAndAverage(int n)

{

long fb1 = 1;

long fb2 = 1;

long fb3 = 2;

long fbn = 0;

long sum = 0;

if (n <= 0) {

System.out.println("Please correct number of items and try again.");

return;

}

System.out.println("The first " + n + " Tribonacci numbers are:");

for(int i = 1; i <= n; i++) {

switch (i) {

case 1: fbn = fb1; break;

case 2: fbn = fb2; break;

case 3: fbn = fb3; break;

default:

fbn = fb1 + fb2 + fb3;

fb1 = fb2;

fb2 = fb3;

fb3 = fbn;

}

sum += fbn;

System.out.print(fbn + " ");

}

System.out.println();

System.out.printf("The sum is %1$d \n", sum);

System.out.printf("The average is %.4f \n", (double)sum / n);

}

}