text: Lucky Numbers |  ; Returns 1 if n is a lucky no . ohterwise returns 0 ; variable next_position is just for readability of the program we can remove it and use n only ; calculate next position of input no ; Driver function to test above function
code: #include <stdio.h> NEW_LINE #define bool  int NEW_LINE bool isLucky ( int n ) { static int counter = 2 ; int next_position = n ; if ( counter > n ) return 1 ; if ( n % counter == 0 ) return 0 ; next_position -= next_position / counter ; counter ++ ; return isLucky ( next_position ) ; } int main ( ) { int x = 5 ; if ( isLucky ( x ) ) printf ( " % d ▁ is ▁ a ▁ lucky ▁ no . " , x ) ; else printf ( " % d ▁ is ▁ not ▁ a ▁ lucky ▁ no . " , x ) ; getchar ( ) ; }