Check if the number is valid when flipped upside down | Java implementation of the approach ; Function that returns true if str is Topsy Turvy ; For every character of the string ; If the current digit cannot form a valid digit when turned upside - down ; Driver code
import java . util . * ; class GFG { static boolean topsyTurvy ( char [ ] str ) { for ( int i = 0 ; i < str . length ; i ++ ) { if ( str [ i ] == '2' str [ i ] == '4' str [ i ] == '5' str [ i ] == '6' str [ i ] == '7' str [ i ] == '9' ) { return false ; } } return true ; } public static void main ( String [ ] args ) { String str = "1234" ; if ( topsyTurvy ( str . toCharArray ( ) ) ) System . out . println ( " Yes " ) ; else System . out . println ( " No " ) ; } }