Help w/ a Prime Number Generator

[Above7heInfluence]

So I need to make a prime number generator that has a class and a main class (a tester). It must take in a user inputted integer and print out all the prime numbers up to that number. I have the class and the main class mostly done but I need a little more help and direction. Any help would be greatly appreciated! Here is my class for it. 

/**   this prints out all prime numbers up to a number inputted..   * author */public class PrimeNumbers{   private boolean isPrime = true;   private int current;     public PrimeNumbers()   {       current = 1;   }   /**      Calculates the next prime number.      @return nextPrime the next prime number if the number is prime.   */   public boolean isPrime(int n)   {       if (n <= 1)           return false;       else if (n > 2 || n % 2 == 0)           return false;       for (int i = 3; i * i <=n; i++)           return n% i != 0;       return false;          }   public int nextPrime()   {       do       {current++;}       while (!isPrime(current));       return current;   }     }

and here is the tester for the class. 

import java.util.Scanner;public class PrimeNumbersTester{   public static void main(String[] args)   {      Scanner in = new Scanner(System.in);            System.out.println("Enter an intger: ");      int n = in.nextInt();      PrimeNumbers fg = new PrimeNumbers();      fg.isPrime(n);      System.out.println(fg.nextPrime());   }}

I know i need to have a loop in the tester but im not sure how to go about the loop. Thank you!

[ilikemacandpc]

Here's a program i Did in my comp scie class that determined if an inputted number was prime. you can go from here

/** * Greetings fellow comrade. Velcome to the Prime-inator! */import java.util.*;public class IsPrime{    public static void main(String[] args)    {        Scanner console = new Scanner(System.in);                System.out.println("Welcome to the Prime Number Determinator!");                double n;          // number inputted        double remain=0;   // the remainder when n is divided by integer p        double p = 2;      // the integer divisors of n -- raise until it equals the squareroot of n                System.out.print("Enter a positive integer for prime-ness determination: ");        n = console.nextDouble();                while (p <= Math.pow(n , 0.5)){            remain = n % p;            p++;            if (remain == 0) {                System.out.println("Your number is not prime (composite).");                break;            }        }                if (remain != 0) {             System.out.println("Your number is prime! Congratulations! One virtual cookie for you!");        }    }}

 

 

Post script: how did you do that formatting?

 

I figured it out!

[Above7heInfluence]

 

Here's a program i Did in my comp scie class that determined if an inputted number was prime. you can go from here

double n;          // number inputted        double remain=0;   // the remainder when n is divided by integer p        double p = 2;      // the integer divisors of n -- raise until it equals the squareroot of n                System.out.print("Enter a positive integer for prime-ness determination: ");        n = console.nextDouble();                while (p <= Math.pow(n , 0.5)){            remain = n % p;            p++;            if (remain == 0) {                System.out.println("Your number is not prime (composite).");                break;            }        }                if (remain != 0) {             System.out.println("Your number is prime! Congratulations! One virtual cookie for you!");        }

Post script: how did you do that formatting?

 

I figured it out!

 

Okay thank you for your post! I just don't understand why it isnt running my methods in the tester class...my teacher wants me to set it up like that but i dont get why it isnt running the methods in the tester...>.<

[madknight3]

Okay thank you for your post! I just don't understand why it isnt running my methods in the tester class...my teacher wants me to set it up like that but i dont get why it isnt running the methods in the tester...>.<

nextPrime is an infinite loop

 

Because this is always returning false due to n > 2

else if (n > 2 || n % 2 == 0)    return false;

[Above7heInfluence]

nextPrime is an infinite loop

How would i change it to fix that? Thank you

[madknight3]

How would i change it to fix that? Thank you

Edited my post to explain

[Above7heInfluence]

Edited my post to explain

Okay so should i just take out the n > 2? And I have an issue implementing the loop in my tester, why is this giving me an error? 

import java.util.Scanner;public class PrimeNumbersTester{   public static void main(String[] args)   {      Scanner in = new Scanner(System.in);            System.out.println("Enter an integer: ");      int n = in.nextInt();      PrimeNumbers fg = new PrimeNumbers();      while (int i = 1; int i<n; i++))      {           fg.isPrime(n);           System.out.println(fg.nextPrime());      }   }}

Thank you!!!

[madknight3]

Okay so should i just take out the n > 2?

That'll stop the infinite loop, but the algorithm is still incorrect.

 

 

And I have an issue implementing the loop in my tester, why is this giving me an error?

Your while loop has syntax errors. int i<n doesn't need the int and there's an extra closing bracket.

[Above7heInfluence]

That'll stop the infinite loop, but the algorithm is still incorrect.

 

 

Your while loop has syntax errors. int i<n doesn't need the int and there's an extra closing bracket.

Okay what will correct the algorithm? Sorry, that im asking so many questions

[Above7heInfluence]

Okay so i got the program to print out prime numbers but it doesnt stop at the number I input? For instance, I input 10 and it prints out to 23 but it should really stop at 7 (since it cant go past 10) ?? here is my tester. 

import java.util.Scanner;public class PrimeNumbersTester{   public static void main(String[] args)   {      Scanner in = new Scanner(System.in);            System.out.println("Enter an integer: ");      int n = in.nextInt();      PrimeNumbers fg = new PrimeNumbers();      int i = 1;      System.out.println("1");      while(i<=n)      {           fg.isPrime(n);           System.out.println(fg.nextPrime());           i++;      }   }}

i tried to put "i++" in the while loop but it gives me an error when i do " while(i<n; i++) " i get an error. 

[madknight3]

You'll need to provide the PrimeNumbers code as well

[Above7heInfluence]

You'll need to provide the PrimeNumbers code as well

I actually figured it out and used my own algorithm for the isPrime method. Thank you for all your help, I guess I easily doubt myself since I'm a beginner and don't understand things very thoroughly yet, thanks again. Glad I can come here for help and get solid help from you and others!!!