write a java program to print the first n prime number and to print the prime number to a given range

Write a java program to print the first n prime number from the user:

A prime number (P) is a number greater than 1 whose only factors are 1 and the number (P) itself. Generally, we can determine a number is prime or not in below steps:

2 is only prime number which is also even number. So, if given number N is 2 the it is PRIME number.

If given number N is even number then it is NOT PRIME number.

Find out square root on N. Traverse all odd numbers up to the sqrt(N) and try to devide the N with current odd number. If remainder is 0 for any odd number then number is NOT PRIME.

Else – number is PRIME.

Program:

import java.util.Scanner;

class AshrafBin

{

 public static void main(String args[])

{

int i,n,n1,count =0;

System.out.print("Enter the number :");

Scanner sc = new Scanner(System.in);

n1= sc.nextInt();

n=2;

while(count<n1)

{

for(i=2; i<n; i++)

{

 if(n%i ==0)

{

break;

}

}

 if(i==n)

{

System.out.println(i);

count++;

}

n++;

}

}

}

Output:

Write a java program to print a prime number to a given range :

import java.util.Scanner;

class PrimeNumbers

{

public static void main (String[] args)

{

int i =0,num =0,n;

String  primeNumbers = "";

Scanner sc= new Scanner(System.in);

System.out.println("Enter the range to be print prime number");

n= sc.nextInt();

for (i = 1; i<= n; i++)         

 {

 int counter=0;

 for(num =i; num>=1; num--){

  if(i%num==0) 

counter = counter + 1;

}

if (counter ==2){

primeNumbers = primeNumbers + i + " ";  

 }

 }

System.out.println("Prime numbers from 1 to " + n +" are :");

System.out.println(primeNumbers);

}

}

Output:

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