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");
}
}
}
}