isprime java

To check if a number is prime in Java, you can use the following approach:

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;
}

This function uses a loop to check if the number n is divisible by any number between 2 and the square root of n. If n is divisible by any of these numbers, it returns false because n is not a prime number. If n is not divisible by any of these numbers, it returns true because n is a prime number.

Here is an example of how to use this function:

System.out.println(isPrime(2)); // Outputs true
System.out.println(isPrime(3)); // Outputs true
System.out.println(isPrime(4)); // Outputs false
System.out.println(isPrime(5)); // Outputs true
System.out.println(isPrime(6)); // Outputs false

In this example, the function isPrime() is called with the numbers 2, 3, 4, 5, and 6 as arguments. It returns true for the prime numbers 2 and 3, and false for the non-prime numbers 4, 5, and 6.

Note that this function has a time complexity of O(√n), which means it becomes slower as the number n gets larger. For large numbers, you may need to use a more efficient algorithm to check if a number is prime.

For more information on prime numbers and algorithms for checking if a number is prime, you can refer to online resources or textbooks on mathematics or computer science.