Given a number n, check whether it’s prime number or not using recursion.
Examples:
Input : n = 11 Output : Yes Input : n = 15 Output : No
The idea is based on school method to check for prime numbers.
C++
// CPP Program to find whether a Number // is Prime or Not using Recursion #include <bits/stdc++.h> using namespace std; // Returns true if n is prime, else // return false. // i is current divisor to check. bool isPrime( int n, int i = 2) { // Base cases if (n <= 2) return (n == 2) ? true : false ; if (n % i == 0) return false ; if (i * i > n) return true ; // Check for next divisor return isPrime(n, i + 1); } // Driver Program int main() { int n = 15; if (isPrime(n)) cout << "Yes" ; else cout << "No" ; return 0; } |
Java
// java Program to find whether a Number // is Prime or Not using Recursion import java.util.*; class GFG { // Returns true if n is prime, else // return false. // i is current divisor to check. static boolean isPrime( int n, int i) { // Base cases if (n <= 2 ) return (n == 2 ) ? true : false ; if (n % i == 0 ) return false ; if (i * i > n) return true ; // Check for next divisor return isPrime(n, i + 1 ); } // Driver program to test above function public static void main(String[] args) { int n = 15 ; if (isPrime(n, 2 )) System.out.println( "Yes" ); else System.out.println( "No" ); } } // This code is contributed by Sam007. |
Python3
# Python 3 Program to find whether # a Number is Prime or Not using # Recursion # Returns true if n is prime, else # return false. # i is current divisor to check. def isPrime(n, i = 2 ): # Base cases if (n < = 2 ): return True if (n = = 2 ) else False if (n % i = = 0 ): return False if (i * i > n): return true # Check for next divisor return isPrime(n, i + 1 ) # Driver Program n = 15 if (isPrime(n)): print ( "Yes" ) else : print ( "No" ) # This code is contributed by # Smitha Dinesh Semwal |
C#
// C# Program to find whether a Number // is Prime or Not using Recursion using System; class GFG { // Returns true if n is prime, else // return false. // i is current divisor to check. static bool isPrime( int n, int i) { // Base cases if (n <= 2) return (n == 2) ? true : false ; if (n % i == 0) return false ; if (i * i > n) return true ; // Check for next divisor return isPrime(n, i + 1); } // Driver code static void Main() { int n = 15; if (isPrime(n, 2)) Console.Write( "Yes" ); else Console.Write( "No" ); } } // This code is contributed by Sam007 |
PHP
<?php // PHP Program to find whether a Number // is Prime or Not using Recursion // Returns true if n is prime, else // return false. // i is current divisor to check. function isPrime( $n , $i = 2) { // Base cases if ( $n <= 2) return ( $n == 2) ? true : false; if ( $n % $i == 0) return false; if ( $i * $i > $n ) return true; // Check for next divisor return isPrime( $n , $i + 1); } // Driver Code $n = 15; if (isPrime( $n )) echo ( "Yes" ); else echo ( "No" ); // This code is contributed by Ajit. ?> |
Output:
No
This article is attributed to GeeksforGeeks.org
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