package ds;

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.Test;

class RecursionTest {

@Test

void testPowerAndFactorial() {

System.out.println("*******power()**********************");

System.out.println(power(2, 4));

System.out.println(power(2, 5));

System.out.println(power(3, 4));

System.out.println(factorial(4));

}

public static double power(double x, int n) {

double y;

if (n == 0) return 1.0;

y = power(x, n/2);

y = y * y;

if (n % 2 == 0) return y;

return x * y;

}

public long factorial(int n) {

if (n == 0) return 1;

return n * factorial(n-1);

}

@Test

void testFibonacci() {

System.out.println("*******fibonacci()**********************");

System.out.println(fib(3));

System.out.println(fib(4));

System.out.println(fib(5));

System.out.println(fib(6));

}

private static int fib (int n) {

if (n == 1 || n == 2) return 1;

return fib(n - 1) + fib(n - 2);

}

@Test

void testDecimalToBinary() {

System.out.println("*******printBinary()**********************");

printBinary(2); System.out.println();

printBinary(3); System.out.println();

printBinary(4); System.out.println();

printBinary(5); System.out.println();

}

private static void printBinary (int n) {

if (n > 0) {

printBinary(n/2);

System.out.printf("%d", n%2);

}

}

}