2019-09-28 11:15:22 +08:00
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package Maths;
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import java.util.Scanner;
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public class PrimeCheck {
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public static void main(String[] args) {
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Scanner scanner = new Scanner(System.in);
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System.out.println("Enter n:");
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int n = scanner.nextInt();
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if (isPrime(n)) {
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System.out.println(n + "is prime number");
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} else {
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System.out.println(n + "is not prime number");
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}
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}
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/***
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* Check a number is prime or not
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* @param n the number
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* @return {@code true} if {@code n} is prime
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*/
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public static boolean isPrime(int n) {
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2019-10-02 06:37:25 +08:00
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if (n == 2) {
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return true;
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}
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if (n < 2 || n % 2 == 0) {
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return false;
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}
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2019-09-28 11:15:22 +08:00
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for (int i = 3; i <= Math.sqrt(n); i += 2) {
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if (n % i == 0) {
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return false;
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}
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}
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return true;
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}
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}
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