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++
#include <bits/stdc++.h>
using namespace std;
bool isPrime( int n, int i = 2)
{
if (n <= 2)
return (n == 2) ? true : false ;
if (n % i == 0)
return false ;
if (i * i > n)
return true ;
return isPrime(n, i + 1);
}
int main()
{
int n = 15;
if (isPrime(n))
cout << "Yes" ;
else
cout << "No" ;
return 0;
}
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Java
import java.util.*;
class GFG {
static boolean isPrime( int n, int i)
{
if (n <= 2 )
return (n == 2 ) ? true : false ;
if (n % i == 0 )
return false ;
if (i * i > n)
return true ;
return isPrime(n, i + 1 );
}
public static void main(String[] args)
{
int n = 15 ;
if (isPrime(n, 2 ))
System.out.println( "Yes" );
else
System.out.println( "No" );
}
}
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Python3
def isPrime(n, i = 2 ):
if (n < = 2 ):
return True if (n = = 2 ) else False
if (n % i = = 0 ):
return False
if (i * i > n):
return True
return isPrime(n, i + 1 )
n = 15
if (isPrime(n)):
print ( "Yes" )
else :
print ( "No" )
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C#
using System;
class GFG
{
static bool isPrime( int n, int i)
{
if (n <= 2)
return (n == 2) ? true : false ;
if (n % i == 0)
return false ;
if (i * i > n)
return true ;
return isPrime(n, i + 1);
}
static void Main()
{
int n = 15;
if (isPrime(n, 2))
Console.Write( "Yes" );
else
Console.Write( "No" );
}
}
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PHP
<?php
function isPrime( $n , $i = 2)
{
if ( $n <= 2)
return ( $n == 2) ? true : false;
if ( $n % $i == 0)
return false;
if ( $i * $i > $n )
return true;
return isPrime( $n , $i + 1);
}
$n = 15;
if (isPrime( $n ))
echo ( "Yes" );
else
echo ( "No" );
?>
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Javascript
<script>
function isPrime(n, i)
{
if (n <= 2)
return (n == 2) ? true : false ;
if (n % i == 0)
return false ;
if (i * i > n)
return true ;
return isPrime(n, i + 1);
}
let n = 15;
if (isPrime(n, 2))
document.write( "Yes" );
else
document.write( "No" );
</script>
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