52 lines
1.6 KiB
Java
52 lines
1.6 KiB
Java
/*
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This is a Java Program to Implement Sieve Of Sundaram Algorithm. This is a program to find all primes less than a number.
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*/
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/**
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** Java Program to implement Sieve Of Sundaram Prime generation
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**/
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import java.util.Scanner;
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/** Class SieveOfSundaram **/
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public class SieveOfSundaram
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{
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/** Function to calculate all primes less than n **/
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private boolean[] calcPrimes(int limit)
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{
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int n = limit/2;
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/** initialize the sieve **/
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boolean[] prime = new boolean[limit];
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for (int i = 1; i < n; i++)
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for (int j = i; j <= (n - i) / (2 * i + 1); j++)
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prime[i + j + 2 * i * j] = true;
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return prime;
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}
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/** Function to get all primes **/
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public void getPrimes(int N)
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{
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boolean[] primes = calcPrimes(N);
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display(primes);
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}
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/** Function to display all primes **/
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public void display(boolean[] primes)
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{
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System.out.print("\nPrimes = 2 3 ");
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for (int i = 2; i < primes.length/2; i++)
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if (!primes[i])
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System.out.print((2 * i + 1) +" ");
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System.out.println();
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}
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/** Main function **/
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public static void main (String[] args)
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{
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Scanner scan = new Scanner(System.in);
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System.out.println("Sieve Of Sundaram Prime Algorithm Test\n");
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/** Make an object of SieveOfSundaram class **/
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SieveOfSundaram sos = new SieveOfSundaram();
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/** Accept n **/
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System.out.println("Enter number to find all primes less than the number\n");
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int n = scan.nextInt();
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sos.getPrimes(n);
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}
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} |