Let's find if a number is prime. A prime number (or a prime) is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. The first few prime numbers are {2, 3, 5, 7, 11, ….}.
Here we have some solutions:
function isPrimeNumber(int $num)
{
for ($i = 2; $i <= $num - 1; $i++) {
if (bcmod($num, $i) == 0) {
return false;
}
}
return ($num == $i);
}
var_dump( isPrimeNumber(4) ); // false
var_dump( isPrimeNumber(11) ); // true
def isPrime(n) :
# Corner cases
if (n <= 1) :
return False
if (n <= 3) :
return True
# This is checked so that we can skip
# middle five numbers in below loop
if (n % 2 == 0 or n % 3 == 0) :
return False
i = 5
while(i * i <= n) :
if (n % i == 0 or n % (i + 2) == 0) :
return False
i = i + 6
return True
# Driver Program
if (isPrime(11)) :
print(" true")
else :
print(" false")
if(isPrime(15)) :
print(" true")
else :
print(" false")
import java.util.Scanner;
import java.util.Scanner;
public class PrimeExample {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.print("Enter a number : ");
int n = s.nextInt();
if (isPrime(n)) {
System.out.println(n + " is a prime number");
} else {
System.out.println(n + " is not a prime number");
}
}
public static boolean isPrime(int n) {
if (n <= 1) {
return false;
}
for (int i = 2; i < Math.sqrt(n); i++) {
if (n % i == 0) {
return false;
}
}
return true;
}
}