In this example, you will learn to check whether an entered number is a prime number or not.
A prime number is a whole number greater than 1 whose only factors are 1 and itself. A factor is a whole number that can be divided evenly into another number. The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29. Numbers that have more than two factors are called composite numbers.
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public class Main { public static void main(String[] args) { int num = 29; boolean flag = false; for(int i = 2; i <= num/2; ++i) { // condition for nonprime number if(num % i == 0) { flag = true; break; } } if (!flag) System.out.println(num + " is a prime number."); else System.out.println(num + " is not a prime number."); } } |
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29 is a prime number. |