Print prime numbers from 1 to N in reverse order | Java program to print all primes between 1 to N in reverse order using Sieve of Eratosthenes ; Create a boolean array " prime [ 0 . . n ] " and initialize all entries it as true . A value in prime [ i ] will finally be false if i is Not a prime , else true . ; If prime [ p ] is not changed , then it is a prime ; Update all multiples of p ; Print all prime numbers ; Driver Program to test above function ; static input ; To display ; reverseorder ( N ) ; calling the function
import java . io . * ; import java . util . * ; class GFG { static void reverseorder ( int n ) { boolean prime [ ] = new boolean [ n + 1 ] ; for ( int i = 0 ; i < n ; i ++ ) prime [ i ] = true ; for ( int p = 2 ; p * p <= n ; p ++ ) { if ( prime [ p ] == true ) { for ( int i = p * 2 ; i <= n ; i += p ) prime [ i ] = false ; } } for ( int i = n ; i >= 2 ; i -- ) if ( prime [ i ] == true ) System . out . print ( i + " ▁ " ) ; } public static void main ( String args [ ] ) { int N = 25 ; System . out . println ( " Prime ▁ number ▁ in ▁ reverse ▁ order " ) ; if ( N == 1 ) System . out . println ( " No ▁ prime ▁ no ▁ exist ▁ in ▁ this ▁ range " ) ; else } }