Question

I need to use a nested for loop to get a list of prime numbers, here is the code:

public static void main(String[] args) {

        for (int i = 2; i <= 10; i++)
        {
            for (int d = 3; d <= 10; d = d + 2)
            {
                 int result = d % i;
                 System.out.println(result);

            }
        }
    }

I think I have the logic right here, but the results was a bit out of mind, any suggestions please ?

Answer 1

What you are doing is only a bit related to finding out prime numbers in that, you are using modulus operator, that is needed, but nothing more than that.

You actually need to make use of the result of that operation.

You can follow the following pseudo-code: –

for i = 2 to 10 {

    1. set a boolean flag for prime to false;

    2. for j = 2 to (i - 1) {  // Since we just need to check modulus till that number
        1. check the result of `i % j`
        2. If any of the result in this loop is `0`, then `i` is not a prime number. 
           So, set the `prime` flag to false, and break out of loop, 
    }
    3. check the value of `prime` flag. If it is `true`, print number is `prime`. 
       Else print not prime 
}

I am not giving away the code, since it would be beneficial for you to try it out on your own. You will learn how to implement a problem statement given in the form of algorithmic steps.