Java Program to Display Prime Numbers from 1 to n
In this Java Program, prime numbers from 1 to n are displayed to the user.
A prime number is a natural number greater than 1 that is not a product of two small natural numbers.
E.g. 2, 3, 5 etc are prime numbers.
Step 1 : Create main method and create the object of Scanner.
Step 2 : Initialize i to zero and num to zero.
Step 3 : Create an empty String named primeNumbers
Step 4 : Ask the user to enter the value of n using System.out.print method
Step 5 : Store the object of Scanner class in variable n
Step 6 : Close the Scanner
Step 7 : Apply For loop where i is equal to 1, i is less than equal to n and increment i by 1
Step 8 : Initialize counter to 0
Step 9 : Apply another for loop where num is equal to i, num is greater than equal to 1 and decrement num by 1
Step 10 : Apply if statement where i % num == 0
Step 11 : Increment counter by 1 and store it in variable counter
Step 12 : Close both the for loops
Step 13 : Apply if statement where counter == 2
Step 14 : Append the Prime number to the String
Step 15 : Print the output
Program :
import java.util.Scanner;
public class PrimeNumbersTwo
{
public static void main(String[]args)
{
Scanner sc = new Scanner(System.in);
int i = 0;
int num = 0;
//Empty String
String primeNumbers = "";
System.out.println("Enter the value of n:");
int n = sc.nextInt();
sc.close();
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)
{
//Appended the Prime number to the String
primeNumbers = primeNumbers + i + " ";
}
}
System.out.println("Prime numbers from 1 to n are:");
System.out.println(primeNumbers);
}
}
Output:
Enter the value of n:
150
Prime numbers from 1 to n are:
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149
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