// Program to check whether a given number // is left-truncatable prime or not. #include   using namespace std; /* Function to calculate x raised to the power y */ int power(int x unsigned int y) {  if (y == 0)  return 1;  else if (y%2 == 0)  return power(x y/2)*power(x y/2);  else  return x*power(x y/2)*power(x y/2); } // Generate all prime numbers less than n. bool sieveOfEratosthenes(int n bool isPrime[]) {  // Initialize all entries of boolean array  // as true. A value in isPrime[i] will finally  // be false if i is Not a prime else true  // bool isPrime[n+1];  isPrime[0] = isPrime[1] = false;  for (int i=2; i<=n; i++)  isPrime[i] = true;  for (int p=2; p*p<=n; p++)  {  // If isPrime[p] is not changed then it is  // a prime  if (isPrime[p] == true)  {  // Update all multiples of p  for (int i=p*2; i<=n; i += p)  isPrime[i] = false;  }  } } // Returns true if n is right-truncatable else false bool leftTruPrime(int n) {  int temp = n cnt = 0 temp1;  // Counting number of digits in the  // input number and checking whether it  // contains 0 as digit or not.  while (temp)  {  cnt++; // counting number of digits.  temp1 = temp%10; // checking whether digit is 0 or not  if (temp1==0)  return false; // if digit is 0 return false.  temp = temp/10;  }  // Generating primes using Sieve  bool isPrime[n+1];  sieveOfEratosthenes(n isPrime);  // Checking whether the number remains prime  // when the leading ('left') digit is successively  // removed  for (int i=cnt; i>0; i--)  {  // Checking number by successively removing  // leading ('left') digit.  /* n=113 cnt=3  i=3 mod=1000 n%mod=113  i=2 mod=100 n%mod=13  i=3 mod=10 n%mod=3 */  int mod= power(10i);  if (!isPrime[n%mod]) // checking prime  return false; // if not prime return false  }  return true; // if remains prime return true } // Driver program int main() {  int n = 113;  if (leftTruPrime(n))  cout << n << ' is left truncatable prime' << endl;  else  cout << n << ' is not left truncatable prime' << endl;  return 0; } 

// Program to check whether  // a given number is left // truncatable prime or not. import java.io.*; class GFG {    // Function to calculate x  // raised to the power y  static int power(int xint y)  {  if (y == 0)  return 1;  else if (y%2 == 0)  return power(x y/2)  *power(x y/2);  else  return x*power(x y/2)  *power(x y/2);  }    // Generate all prime   // numbers less than n.  static void sieveOfEratosthenes  (int n boolean isPrime[])  {    // Initialize all entries of boolean  // array as true. A value in isPrime[i]  // will finally be false if i is Not  // a prime else true bool isPrime[n+1];  isPrime[0] = isPrime[1] = false;  for (int i = 2; i <= n; i++)  isPrime[i] = true;    for (int p = 2; p*p <= n; p++)  {  // If isPrime[p] is not changed  // then it is a prime  if (isPrime[p] == true)  {    // Update all multiples of p  for (int i = p*2; i <= n; i += p)  isPrime[i] = false;  }  }  }    // Returns true if n is   // right-truncatable else false  static boolean leftTruPrime(int n)  {  int temp = n cnt = 0 temp1;    // Counting number of digits in the  // input number and checking whether  // it contains 0 as digit or not.  while (temp != 0)  {  // counting number of digits.  cnt++;     temp1 = temp%10;    // checking whether digit is  // 0 or not  if (temp1 == 0)  return false;  temp = temp/10;  }    // Generating primes using Sieve  boolean isPrime[] = new boolean[n+1];  sieveOfEratosthenes(n isPrime);    // Checking whether the number  // remains prime when the leading  // ('left') digit is successively removed  for (int i = cnt; i > 0; i--)  {  // Checking number by successively  // removing leading ('left') digit.  /* n=113 cnt=3  i=3 mod=1000 n%mod=113  i=2 mod=100 n%mod=13  i=3 mod=10 n%mod=3 */  int mod = power(10i);    if (!isPrime[n%mod])   return false;   }    // if remains prime return true  return true;   }    // Driver program  public static void main(String args[])  {  int n = 113;    if (leftTruPrime(n))  System.out.println  (n+' is left truncatable prime');  else  System.out.println  (n+' is not left truncatable prime');  } } /*This code is contributed by Nikita Tiwari.*/ 

# Python3 Program to  # check whether a  # given number is left # truncatable prime  # or not. # Function to calculate  # x raised to the power y  def power(x y) : if (y == 0) : return 1 elif (y % 2 == 0) : return(power(x y // 2) * power(x y // 2)) else : return(x * power(x y // 2) * power(x y // 2)) # Generate all prime  # numbers less than n. def sieveOfEratosthenes(n isPrime) : # Initialize all entries # of boolean array # as true. A value in # isPrime[i] will finally # be false if i is Not a # prime else true # bool isPrime[n+1]; isPrime[0] = isPrime[1] = False for i in range(2 n+1) : isPrime[i] = True p=2 while(p * p <= n) : # If isPrime[p] is not # changed then it is # a prime if (isPrime[p] == True) : # Update all multiples # of p i=p*2 while(i <= n) : isPrime[i] = False i = i + p p = p + 1 # Returns true if n is # right-truncatable  # else false def leftTruPrime(n) : temp = n cnt = 0 # Counting number of # digits in the input # number and checking # whether it contains # 0 as digit or not. while (temp != 0) : # counting number  # of digits. cnt=cnt + 1 # checking whether # digit is 0 or not temp1 = temp % 10; if (temp1 == 0) : # if digit is 0 # return false. return False temp = temp // 10 # Generating primes  # using Sieve isPrime = [None] * (n + 1) sieveOfEratosthenes(n isPrime) # Checking whether the # number remains prime # when the leading  # ('left') digit is # successively removed for i in range(cnt 0 -1) : # Checking number by  # successively removing # leading ('left') digit. # n=113 cnt=3 # i=3 mod=1000 n%mod=113 # i=2 mod=100 n%mod=13 # i=3 mod=10 n%mod=3  mod = power(10 i) # checking prime if (isPrime[n % mod] != True) : # if not prime # return false return False # if remains prime #  return true return True # Driver program n = 113 if (leftTruPrime(n)) : print(n 'is left truncatable prime') else : print(n 'is not left truncatable prime') # This code is contributed by Nikita Tiwari. 

// Program to check whether  // a given number is left // truncatable prime or not. using System; class GFG {    // Function to calculate x  // raised to the power y  static int power(int x int y)  {  if (y == 0)  return 1;  else if (y%2 == 0)  return power(x y/2)  *power(x y/2);  else  return x*power(x y/2)  *power(x y/2);  }    // Generate all prime   // numbers less than n.  static void sieveOfEratosthenes  (int n bool []isPrime)  {  // Initialize all entries of boolean  // array as true. A value in isPrime[i]  // will finally be false if i is Not  // a prime else true bool isPrime[n+1];  isPrime[0] = isPrime[1] = false;  for (int i = 2; i <= n; i++)  isPrime[i] = true;    for (int p = 2; p * p <= n; p++)  {  // If isPrime[p] is not changed  // then it is a prime  if (isPrime[p] == true)  {  // Update all multiples of p  for (int i = p * 2; i <= n; i += p)  isPrime[i] = false;  }  }  }    // Returns true if n is   // right-truncatable else false  static bool leftTruPrime(int n)  {  int temp = n cnt = 0 temp1;    // Counting number of digits in the  // input number and checking whether  // it contains 0 as digit or not.  while (temp != 0)  {  // counting number of digits.  cnt++;     temp1 = temp%10;    // checking whether digit is  // 0 or not  if (temp1 == 0)  return false;  temp = temp/10;  }    // Generating primes using Sieve  bool []isPrime = new bool[n+1];  sieveOfEratosthenes(n isPrime);    // Checking whether the number  // remains prime when the leading  // ('left') digit is successively removed  for (int i = cnt; i > 0; i--)  {  // Checking number by successively  // removing leading ('left') digit.  /* n=113 cnt=3  i=3 mod=1000 n%mod=113  i=2 mod=100 n%mod=13  i=3 mod=10 n%mod=3 */  int mod = power(10 i);    if (!isPrime[n%mod])   return false;   }    // if remains prime return true  return true;   }    // Driver program  public static void Main()  {  int n = 113;    if (leftTruPrime(n))  Console.WriteLine  (n + ' is left truncatable prime');  else  Console.WriteLine  (n + ' is not left truncatable prime');  } }   //This code is contributed by Anant Agarwal. 

 // PHP Program to check whether a // given number is left-truncatable // prime or not. /* Function to calculate x raised to the power y */ function power($x $y) { if ($y == 0) return 1; else if ($y % 2 == 0) return power($x $y/2) * power($x $y/2); else return $x*power($x $y/2) * power($x $y/2); } // Generate all prime numbers // less than n. function sieveOfEratosthenes($n $l $isPrime) { // Initialize all entries of  // boolean array as true. A  // value in isPrime[i] will  // finally be false if i is  // Not a prime else true // bool isPrime[n+1]; $isPrime[0] = $isPrime[1] = -1; for ($i = 2; $i <= $n; $i++) $isPrime[$i] = true; for ( $p = 2; $p * $p <= $n; $p++) { // If isPrime[p] is not  // changed then it is // a prime if ($isPrime[$p] == true) { // Update all multiples // of p for ($i = $p * 2; $i <= $n; $i += $p) $isPrime[$i] = false; } } } // Returns true if n is  // right-truncatable else false function leftTruPrime($n) { $temp = $n; $cnt = 0; $temp1; // Counting number of digits in // the input number and checking // whether it contains 0 as digit // or not. while ($temp) { // counting number of digits. $cnt++; // checking whether digit is // 0 or not $temp1 = $temp % 10; if ($temp1 == 0) // if digit is 0 return // false. return -1; $temp = $temp / 10; } // Generating primes using Sieve $isPrime[$n + 1]; sieveOfEratosthenes($n $isPrime); // Checking whether the number // remains prime when the leading // ('left') digit is successively // removed for ($i = $cnt; $i > 0; $i--) { // Checking number by  // successively removing // leading ('left') digit. /* n=113 cnt=3  i=3 mod=1000 n%mod=113  i=2 mod=100 n%mod=13  i=3 mod=10 n%mod=3 */ $mod= power(10 $i); // checking prime if (!$isPrime[$n % $mod]) // if not prime return // false return -1; } // if remains prime return true return true; } // Driver program $n = 113; if (leftTruPrime($n)) echo $n ' is left truncatable' ' prime' 'n'; else echo $n ' is not left ' 'truncatable prime' 'n'; // This code is contributed by ajit ?> 

<script> // Javascript program to check whether  // a given number is left // truncatable prime or not.  function power(x y)  {  if (y == 0)  return 1;  else if (y%2 == 0)  return power(x Math.floor(y/2))  *power(x Math.floor(y/2));  else  return x*power(x Math.floor(y/2))  *power(x Math.floor(y/2));  }    // Generate all prime   // numbers less than n.  function sieveOfEratosthenes  (n isPrime)  {    // Initialize all entries of boolean  // array as true. A value in isPrime[i]  // will finally be false if i is Not  // a prime else true bool isPrime[n+1];  isPrime[0] = isPrime[1] = false;  for (let i = 2; i <= n; i++)  isPrime[i] = true;    for (let p = 2; p*p <= n; p++)  {  // If isPrime[p] is not changed  // then it is a prime  if (isPrime[p] == true)  {    // Update all multiples of p  for (let i = p*2; i <= n; i += p)  isPrime[i] = false;  }  }  }    // Returns true if n is   // right-truncatable else false  function leftTruPrime(n)  {  let temp = n cnt = 0 temp1;    // Counting number of digits in the  // input number and checking whether  // it contains 0 as digit or not.  while (temp != 0)  {  // counting number of digits.  cnt++;     temp1 = temp%10;    // checking whether digit is  // 0 or not  if (temp1 == 0)  return false;  temp = Math.floor(temp/10);  }    // Generating primes using Sieve  let isPrime = Array.from({length: n+1} (_ i) => 0);  sieveOfEratosthenes(n isPrime);    // Checking whether the number  // remains prime when the leading  // ('left') digit is successively removed  for (let i = cnt; i > 0; i--)  {  // Checking number by successively  // removing leading ('left') digit.  /* n=113 cnt=3  i=3 mod=1000 n%mod=113  i=2 mod=100 n%mod=13  i=3 mod=10 n%mod=3 */  let mod = power(10i);    if (!isPrime[n%mod])   return false;   }    // if remains prime return true  return true;   } // Driver Code  let n = 113;    if (leftTruPrime(n))  document.write  (n+' is left truncatable prime');  else  document.write  (n+' is not left truncatable prime'); // This code is contributed by sanjoy_62. </script>