for(int i = 2 ; i <= num ; i++)
{
if(isPrime(i))
{
System.out.print(" " + i);
cnt++;
}
}
System.out.println("Prime numbers = " + cnt);
}
public static boolean isPrime(int i) {
for (int j = 2; j <= Math.sqrt(i); j++) {
if(i % j == 0)
{
return false;
}
}
return true;
}
import java.util.Scanner;
public class Main
{
public static void main (String[] args)
{
Scanner scanner = new Scanner(System.in);
int i =0;
int num =0;
//Empty String
String primeNumbers = "";
System.out.println("Enter the value of n:");
int n = scanner.nextInt();
scanner.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);
}
}
import java.util.*;
class Example{
public static boolean isPrime(int num){
for(int i=2; i<num; i++){
if(num%i==0){
return false;
}
}
return true;
}
public static void main(String args[]){
for (int i = 0; i < 1000; i++){
if(isPrime(i)){
System.out.println(i);
}
}
}
}
public class PrimeExample2{
static void checkPrime(int n){
int i,m=0,flag=0;
m=n/2;
if(n==0||n==1){
System.out.println(n+" is not prime number");
}else{
for(i=2;i<=m;i++){
if(n%i==0){
System.out.println(n+" is not prime number");
flag=1;
break;
}
}
if(flag==0) { System.out.println(n+" is prime number"); }
}//end of else
}
public static void main(String args[]){
checkPrime(1);
checkPrime(3);
checkPrime(17);
checkPrime(20);
}
}
// The following method returns a boolean indicating
// if the parameter is a prime number
private boolean isPrimeNaiveIter(int val) {
if(val == 0 || val == 1)
return false;
if(val == 2)
return true;
// Look for a divisor other than 1 and val
for(int div = 2; div*div <= val; div++) {
// if found return false
if(val % div==0)
return false;
}
// No divisors found => return it is a prime number
return true;
}
public class PrimeNumbers {
public static void main(String[] args) {
int num = 20, count;
for (int i = 1; i <= num; i++) {
count = 0;
for (int j = 2; j <= i / 2; j++) {
if (i % j == 0) {
count++;
break;
}
}
if (count == 0) {
System.out.println(i+"is prime number");
}
}
}
}
Program Output:
public class PrimeExample{
public static void main(String args[]){
int i,m=0,flag=0;
int n=3;//it is the number to be checked
m=n/2;
if(n==0||n==1) System.out.println(n+" is not prime number");
else{
for(i=2;i<=m;i++) if(n%i==0) {
System.out.println(n+" is not prime number");
flag=1;
break;
}
if(flag==0) System.out.println(n+" is prime number");
}//end of else
}
}