The following program checks (find) whether a number is prime or not. It also prints all prime numbers between 1 to the number input by user.
The Program shows output as :
Enter number to check prime : 13
Entered Number is a Prime Number
Prime Number between 1 to 13
2 3 5 7 11 13
Total Prime Number : 6
// Java Prime Number Program
import java.util.Scanner;
class Number
{
// Checks if the number is prime or not
public void primeNumber(int num)
{
boolean flag=true;
if(num > 1)
{
for(int i=2; i< num/2; i++)
{
if(num%i==0)
{
flag=false;
break;
}
}
if(flag)
System.out.println("Entered Number is a Prime Number ");
else
System.out.println("Entered Number is Not a Prime Number ");
}
else
System.out.println("Not a Prime Number ");
}
// Lists or print all prime numbers between 1 to num ( num=100 or any value )
public void listPrimeNumber(int num)
{
boolean flag=true;
int j, countPrime=0;
System.out.println("Prime number between 1 to " + num);
for(int i=2; i<=num; i++)
{
for(j=2; j<=i/2; j++)
{
if(i%j==0)
{
flag=false;
break;
}
}
if(flag)
{
countPrime+=1;
System.out.println(i + " ");
}
else
{
flag = true;
}
}
if(countPrime==0)
{
System.out.println("No Prime Number exist ");
}
else
{
System.out.println("\nTotal Prime Numbers : " + countPrime);
}
}
public static void main(String args[])
{
Number prime=new Number();
int num;
Scanner input=new Scanner(System.in);
System.out.println("Enter the number to check prime : ");
num = input.nextInt();
prime.primeNumber(num);
prime.listPrimeNumber(num);
}
}