Java:Counting prime numbers

Question

So I have written this code, and I am proud of it since I have not been coding for a long time. What it does, it asks for a number and then prints all the Prime numbers there are from 1 to that number.

import java.util.Scanner;
class PrimeNumberExample {

    public static void main(String args[]) {

        //get input till which prime number to be printed
        System.out.println("Enter the number till which prime number to be printed: ");
        int limit = new Scanner(System.in).nextInt();

        //printing primer numbers till the limit ( 1 to 100)
        System.out.println("Printing prime number from 1 to " + limit);
        for(int number = 2; number<=limit; number++){
            //print prime numbers only
            if(isPrime(number)){
                System.out.println(number);
            }
        }

    }

    /*
     * Prime number is not divisible by any number other than 1 and itself
     * @return true if number is prime
     */
    public static boolean isPrime(int number){
        for(int i=2; i<number; i++){
            if(number%i == 0){
                return false; //number is divisible so its not prime
            }
        }
        return true; //number is prime now
    }
}

But, what I would like it to do is ask for a number, let us take 10 and then print the first 10 prime numbers, I have tried to see if I could find a way, but I do not know how to since I have not used java that much. I hope that you can and will help me.

Answer 1

Just count how many primes number have been printed so far. If this number is more than 10 then stop. Your loop should be like that:

for(int number = 2; number<=limit; number++){
            //print prime numbers only
            if(isPrime(number)){
                System.out.println(number);
                count++; 
            }
        }

Whole code:

import java.util.Scanner;
class PrimeNumberExample {

    public static void main(String args[]) {

        //get input till which prime number to be printed
        System.out.println("Enter the amount of prime numbers to be printed: ");
        int limit = new Scanner(System.in).nextInt();
        int count=0;

        //printing primer numbers till the limit ( 1 to 100)
        System.out.println("Printing prime number from 1 to " + limit);
        for(int number = 2; number<=limit; number++){
            //print prime numbers only
            if(isPrime(number)){
                System.out.println(number);
                count++; 
            }
        }

    }

    /*
     * Prime number is not divisible by any number other than 1 and itself
     * @return true if number is prime
     */
    public static boolean isPrime(int number){
        for(int i=2; i<number; i++){
            if(number%i == 0){
                return false; //number is divisible so its not prime
            }
        }
        return true; //number is prime now
    }
}

Answer 2

Try this:

public static void main(String[] args) throws Exception {

    // get input till which prime number to be printed
    System.out.println("Enter the number till which prime number to be printed: ");
    int limit = new Scanner(System.in).nextInt();

    // printing primer numbers till the limit ( 1 to 100)
    System.out.printf("Printing first %d prime numbers\n", limit);
    for (int number = 2; limit > 0; number++) {
        if (isPrime(number)) {
            System.out.println(number);
            limit--;
        }
    }
}

/*
 * Prime number is not divisible by any number other than 1 and itself
 * 
 * @return true if number is prime
 */
public static boolean isPrime(int number) {
    for (int i = 2; i < number; i++) {
        if (number % i == 0) {
            return false; // number is divisible so its not prime
        }
    }
    return true; // number is prime now
}