Java basic written test programming questions

Fibonacci sequence

package javabasic;

public class Fibonacci {
	/*
	 * Fibonacci sequence
	 */
	public static void main(String[] args) {
		int f[] = new int[10];
		f[0] = 1;
		System.out.println("The first Fibonacci number: " + f[0]);
		f[1] = 1;
		System.out.println("2nd Fibonacci number: " + f[1]);
		for(int i=2; i<f.length; i++){
			f[i] = f[i-1] + f[i-2];
			System.out.println("th" + (i+1) + "Fibonacci number: " + f[i]);
		}
	}
}

Prime / quality

package javabasic;

public class Prime {
	/*
	 * Prime number
	 */
	public static void main(String[] args) {
		for(int i = 2; i <= 100; i++){
			boolean flag = true;
			for(int j = 2; j <= Math.sqrt(i); j++){
				if(i%j == 0){
					flag = false;
					break;
				}
			}
			if(flag == true){
				System.out.print(i+" ");
			}
		}
	}
}

Perfect number

package javabasic;

public class Perfact {
	/*
	 * Perfect number
	 */
	public static void main(String[] args) {
		for(int i = 1; i <= 1000; i++){
			int sum = 0;
			for(int j = 1; j < i; j++){
				if(i % j == 0){
					sum = sum + j;
				}
			}
			if(sum == i){
				System.out.println(i);
			}
		}
	}
}

number of daffodils

package javabasic;

public class Narcissistic {
	/*
	 * Number of daffodils
	 * n-digit integer (n>=3), which is exactly the sum of its n-digit powers.  
	 */
	public static void main(String[] args) {
		// three daffodils number
		for(int i = 100; i < 1000; i++){
			int a = i / 100;
			int b = i / 10 % 10;
			int c = i % 10;
			if(i == Math.pow(a, 3) + Math.pow(b, 3) + Math.pow(c, 3)){
				System.out.print(i+"\t");
			}
		}
	}
}