prime numbers java algorithm code example
Example 1: how to check if number prime in java
public class PrimeNumberInJava
{
public static void main(String[] args)
{
int a, b = 0, flag = 0;
int number = 17;
b = number / 2;
if(number == 0 || number == 1)
{
System.out.println(number + " is not prime number");
}
else
{
for(a = 2; a <= b; a++)
{
if(number % a == 0)
{
System.out.println(number + " is not prime number.");
flag = 1;
break;
}
}
if(flag == 0)
{
System.out.println(number + " is prime number.");
}
}
}
}
Example 2: primenumbers java
It will display the prime numbers between 1 and 100.
class PrimeNumbers
{
public static void main (String[] args)
{
int i =0;
int num =0;
String primeNumbers = "";
for (i = 1; i <= 100; 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 100 are :");
System.out.println(primeNumbers);
}
}