Prime numbers are numbers that can only be divided by themselves or by one. i.e.
A number is said to be prime if it is having one and itself as the only divisors.
The following example shows how to check whether the given number is prime.
/**
* A number is said to be prime if it is having one and itself as the only divisors.
*
* @author Sudhakar KV
*
*/ public class PrimeNumber {
/**
* @param args
*/ public static void main(String[] args) { for (int i = 0 ; i < 20 ; i ++) { if(isPrimeNumber(i)) {
System.out.println(i + " is a prime number");
} else {
System.out.println(i + " is not a prime number");
}
}
}
private static boolean isPrimeNumber(int number) { boolean prime = true;
number = Math.abs(number);
if (number < 2) {
prime = false;
} else { for (int i = 2 ; i <= number/2 ; i ++) { if (number % i == 0) {
prime = false; break;
}
}
} return prime;
}
}
It gives the following output,
0 is not a prime number
1 is not a prime number
2 is a prime number
3 is a prime number
4 is not a prime number
5 is a prime number
6 is not a prime number
7 is a prime number
8 is not a prime number
9 is not a prime number
10 is not a prime number
11 is a prime number
12 is not a prime number
13 is a prime number
14 is not a prime number
15 is not a prime number
16 is not a prime number
17 is a prime number
18 is not a prime number
19 is a prime number
