tag:blogger.com,1999:blog-694855878384792308.post8911901730611528935..comments2024-03-21T06:26:49.387-07:00Comments on Java67: How to Check if Given Number is Prime in Java - With Examplejavin paulhttp://www.blogger.com/profile/15028902221295732276noreply@blogger.comBlogger45125tag:blogger.com,1999:blog-694855878384792308.post-14743212787475112102023-03-21T23:18:48.113-07:002023-03-21T23:18:48.113-07:00package com.InterviewQuestions;
import java.util.S...package com.InterviewQuestions;<br />import java.util.Scanner;<br /><br />public class Prime <br />{<br /> public static void main(String[] args) <br /> {<br /> Scanner sc = new Scanner(System.in);<br /> int count=0;<br /> System.out.println("Enter Number to check whether its Prime or Not");<br /> int number = sc.nextInt();<br /><br /> if(number<=1)<br /> {<br /> System.out.println("Not a Prime Number");<br /> }<br /> <br /> <br /> for(int i=2;i<=number/2;i++)<br /> {<br /> if(number%i==0)<br /> {<br /> count++;<br /> } <br /> }<br /><br /> if(count>=1)<br /> {<br /> System.out.println("Not a Prime Number");<br /> }<br /> else<br /> {<br /> System.out.println("Prime Number");<br /> }<br /> <br /> sc.close(); <br /> } <br />}Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-66181912464602123062022-04-05T23:07:10.410-07:002022-04-05T23:07:10.410-07:001 is a composite number so we have to initialize i...1 is a composite number so we have to initialize i to 2.Raghavendra.gahttps://www.blogger.com/profile/05086104639456796170noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-7496395767402166402021-09-22T10:13:42.510-07:002021-09-22T10:13:42.510-07:00import java.util.Scanner;
public class Prime {
...<br />import java.util.Scanner;<br /><br />public class Prime {<br /><br /> public static void main(String[] args) {<br /> Scanner sc = new Scanner(System.in);<br /> int n;<br /><br /> while (true) {<br /> System.out.println("Enter the number : ");<br /> n = sc.nextInt();<br /> int count=0;<br /> for(int i = 1 ; i<=n ; i++) {<br /> if (n % i == 0) {<br /> count++;<br /> }<br /> }<br /> if(count > 2) {<br /> System.out.println(n + " is not prime Number");<br /> } else {<br /> System.out.println(n + " is prime Number");<br /> }<br /> }<br /><br /> }<br /><br />}<br /><br /><br />Anonymoushttps://www.blogger.com/profile/11119165768351280705noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-64723775707317044072021-01-11T18:38:32.674-08:002021-01-11T18:38:32.674-08:00private static boolean isPrime(int num) {
boolea... private static boolean isPrime(int num) {<br /> boolean isprime=false;<br /> if(num/num==1 && num%2!=0) {<br /> if(num%3!=0) {<br /> isprime=true;<br /> }<br /> }<br /> return isprime||num==2||num==3;<br /> <br /> }Anonymoushttps://www.blogger.com/profile/06364182535356311699noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-45340866142964443352020-11-30T20:29:51.015-08:002020-11-30T20:29:51.015-08:00Yes, you are correct, it seems something is wrong ...Yes, you are correct, it seems something is wrong with the logic, I will take a look. thx for pointing it out. javin paulhttps://www.blogger.com/profile/15028902221295732276noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-49936496199795922652020-11-30T01:49:21.270-08:002020-11-30T01:49:21.270-08:00The third way to checks seems to be wrong. It show...The third way to checks seems to be wrong. It shows numbers like 25, 35, 49, 55, 65, 77, 85, 91, 95, 115, 119, 121, 125, 133, 143, 145, 155, 161, 169, 175, 185, 187 etc. as prime. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-40136376975278601742020-07-17T23:43:45.199-07:002020-07-17T23:43:45.199-07:00I think you have implemented wrongly. how come 15 ...I think you have implemented wrongly. how come 15 will be prime as per the code.<br />for 15 as a number, <br />int sqrt = (int) Math.sqrt(number) + 1; // sqrt = 4;<br />loop will run only once as i < 4<br />for (int i = 3; i < sqrt; i += 2) {<br />then 15 % 3 == 0, so it return false. False mean its not a Prime number.<br /><br />Try same thing with 5 also.<br />sqrt value of 5 will 3 i.e. (int) Math.sqrt(number) + 1;<br />so the condition(i < sqrt) of for loop(3 < 3) is false so it won't get into and hence 5 is a Prime number.<br />vidya bhushanhttps://www.blogger.com/profile/02137246189750664093noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-12789956134326488002020-05-03T08:47:57.272-07:002020-05-03T08:47:57.272-07:00public class PrimeNumber {
public static boolea...public class PrimeNumber {<br /> <br /> public static boolean prime(int n) {<br /> boolean isPrime = true;<br /><br /> for(int i = 2; i<n;i++) { //prime numbers can be divided by 1 and itself. <br /> isPrime = (n%i==0)&&(n!=2)&&(n!=1)? false:true; <br /> if(isPrime == false) break; //if isPrime is false, it is not a prime number, therefore the loop should not continue<br /> }<br /> return isPrime;<br /> }<br /><br /> public static void main(String[] args) {<br /><br /> Scanner in = new Scanner(System.in); <br /> System.out.print("Enter a number: "); //user input<br /> int n = in.nextInt(); <br /><br /> String output= (prime(n) == true)? " is a prime number":" is NOT a prime number"; //output condition. <br /> System.out.println(n+output);<br /> in.close();<br /> <br /> }<br />}Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-83882204377428884592020-04-08T20:37:53.336-07:002020-04-08T20:37:53.336-07:00import java.util.Scanner;
class PrintPrime
{
publ...import java.util.Scanner;<br />class PrintPrime<br />{<br /> public static void main(String[] args) {<br /> Scanner s=new Scanner(System.in);<br /> System.out.println("Enter the number upto print");<br /> int num=s.nextInt();<br /> System.out.println("prime number from");<br /> int from=s.nextInt();<br /> System.out.println("the prime number series is: ");<br /> for (int i=from;i<=num;i++ ) {<br /> int count=0;<br /> for (int j=1;j<=i ;j++) {<br /> if(i%j==0)<br /> {<br /> count++;<br /> }<br /> }<br /> if(count==2)<br /> {<br /> System.out.print(i+" ");<br /> }<br /> }<br /> }<br />}Gyanhttps://www.blogger.com/profile/12007400347386859536noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-4716709871021421202020-04-08T18:31:11.916-07:002020-04-08T18:31:11.916-07:00import java.util.Scanner;
class IsPrime
{
public ...import java.util.Scanner;<br />class IsPrime<br />{<br /> public static void main(String[] args) {<br /> Scanner s=new Scanner(System.in);<br /> System.out.println("Enter the number checked prime or not");<br /> int num=s.nextInt();<br /> if(num==0||num==1)<br /> {<br /> System.out.println("not a prime number");<br /> }<br /> else<br /> {int count=0;<br /> for (int i=2;i<=num ;i++ ) {<br /> if (num%i==0) {<br /> count++;<br /> }<br /> }<br /> if(count==1)<br /> {<br /> System.out.println(num+" is a prime number");<br /> }<br /> else{<br /> System.out.println(num+" is not a prime number");<br /> }<br /> }<br /> }<br /> }<br />Gyanhttps://www.blogger.com/profile/12007400347386859536noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-76674283799638870592020-03-11T07:30:15.757-07:002020-03-11T07:30:15.757-07:00Hi friends every one is doing a great job on wheth...Hi friends every one is doing a great job on whether the number is prime or not.<br />But I have two question is following in the below<br />Print prime numbers between given intervals/numbers?<br />Or<br />Print Prime numbers from given number<br />(Like if you enter 5 then print prime numbers after 5 only)Aswinihttps://www.blogger.com/profile/12889445176476551654noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-52700508953652664342020-03-04T17:20:49.415-08:002020-03-04T17:20:49.415-08:00Hey here is a logic!
class Emmanuel{
public stati...Hey here is a logic!<br /><br />class Emmanuel{<br />public static void main(String [] args){<br />for(int i = 2; i<=50; i++){<br /> for (int j = 2; j<=i; j++){<br /> if(j==i)<br /><br />System.out.println(i);<br />}<br /><br />if (i%j==0){<br />break;<br />}<br />}<br />}<br />}<br />}<br />Anonymoushttps://www.blogger.com/profile/08645665364376356485noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-74731491413803297822020-03-03T02:51:24.491-08:002020-03-03T02:51:24.491-08:00Simple Way....
int a= 5;
int div=2;
While(a>...Simple Way....<br /><br />int a= 5;<br /><br />int div=2;<br /><br />While(a>div)<br />{<br /> if(a%div==0){<br /> break;<br /> }div++;<br />}<br />if(a==div)<br /> System.out.print("Prime Number");<br />else<br /> System.out.print("Not Prime Number");Anonymoushttps://www.blogger.com/profile/01552510292818235679noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-2247860532255786482019-12-23T05:38:29.422-08:002019-12-23T05:38:29.422-08:00import java.util.Scanner;
public class PrimeNumb...import java.util.Scanner;<br /><br /><br />public class PrimeNumber {<br /><br /> /**<br /> * @param args<br /> */<br /> public static void main(String[] args) {<br /> int count = 0;<br /> System.out.println("Enter a number");<br /> int n=new Scanner(System.in).nextInt();<br /> for(int i=1;i<=n;i++){<br /> if(n%i==0){<br /> count++;<br /> }<br /> }<br /> if(count==2){<br /> System.out.println(n+"is a Prime number");<br /> }<br /> else{<br /> System.out.println(n+"Not a Prime number");<br /> }<br /><br /> }<br /><br />}Angan Dashttps://www.blogger.com/profile/16121918461760381438noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-27521600601102293842019-12-08T13:43:33.453-08:002019-12-08T13:43:33.453-08:00int num = 131;
if(!((num%2==0)||(num%3==0)||(nu...int num = 131; <br /> if(!((num%2==0)||(num%3==0)||(num%5==0)||(num%7==0)||(num%10==0))) {<br /> System.out.println("num \""+ num +"\" is prime");<br /> }else {<br /> System.out.println("num \""+ num +"\" is NOT prime");<br /> }<br /><br />is this a valid approach?sriramhttps://www.blogger.com/profile/14021644489847151008noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-45814360097766349702019-11-30T03:04:44.287-08:002019-11-30T03:04:44.287-08:00Not Valid
can you check 25?
its show prime noNot Valid<br /><br />can you check 25?<br />its show prime noMOHANhttps://www.blogger.com/profile/12949882622673168871noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-37695774941522912892019-07-18T02:35:13.163-07:002019-07-18T02:35:13.163-07:00Well 15697 is not prime but if ((num * num - 1) % ...Well 15697 is not prime but if ((num * num - 1) % 24 == 0) will be true for it. Sagar Gohilnoreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-89720728108130348472019-03-16T11:44:09.724-07:002019-03-16T11:44:09.724-07:00int sqrt = (int) Math.sqrt(number) + 1;
for (int ...int sqrt = (int) Math.sqrt(number) + 1; <br />for (int i = 3; i < sqrt; i += 2) { <br />if (number % i == 0) { <br />return false; <br />} <br />}<br /><br />This is flawed. 15 returns as prime. 15 % 3 is 0. I made an if statement, that could be implemented as a switch, that checks the number if it is divisible by the first 4 natural prime numbers (2, 3, 5, 7).<br />sleepybulletshttps://www.blogger.com/profile/08530844593404989861noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-55258259761475156752019-03-16T11:41:35.164-07:002019-03-16T11:41:35.164-07:00int sqrt = (int) Math.sqrt(number) + 1;
for (...int sqrt = (int) Math.sqrt(number) + 1; <br /> for (int i = 3; i < sqrt; i += 2) { <br /> if (number % i == 0) { return false; <br /> } <br />}<br /><br /><br />This is a flawed approach. It counts 15 as a prime, where 5 is not (15 % 3 = 0).sleepybulletshttps://www.blogger.com/profile/08530844593404989861noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-55470656933280504102018-12-07T08:13:33.652-08:002018-12-07T08:13:33.652-08:00public class Test {
public static void main(Stri...<br />public class Test {<br /><br /> public static void main(String[] args) {<br /> int number = 111;<br /> for(int i=2;i<Math.sqrt(number);i++) {<br /> if(number%i==0) {<br /> System.out.println("nt prime number" + i);<br /> return;<br /> } <br /> }<br /> System.out.println(" prime");<br /> }<br />}<br />Anonymoushttps://www.blogger.com/profile/05552598078595533616noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-30316937553211767472018-11-01T22:54:05.021-07:002018-11-01T22:54:05.021-07:00Thanks alotThanks alotAnonymoushttps://www.blogger.com/profile/17159130359916629541noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-22598737866609956772018-10-12T03:23:35.632-07:002018-10-12T03:23:35.632-07:00please verify whether it is valid:
public class t...please verify whether it is valid:<br /><br />public class task {<br /><br /> public static void main(String[] args) {<br /> int a=238;<br /> if(((a%2==0)||(a%3==0))&&((a!=2)||(a!=3))) {<br /> System.out.print("given num is not prime");<br /> }<br /> else {<br /> System.out.print("given num is prime");<br /> }<br /> }<br /><br />}anonymoushttps://www.blogger.com/profile/11166353202229387268noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-7923236634116739552018-10-12T03:22:43.734-07:002018-10-12T03:22:43.734-07:00hi,
please verify whether it is correct:
public c...hi,<br />please verify whether it is correct:<br /><br />public class task {<br /><br /> public static void main(String[] args) {<br /> int a=238;<br /> if(((a%2==0)||(a%3==0))&&((a!=2)||(a!=3))) {<br /> System.out.print("given num is not prime");<br /> }<br /> else {<br /> System.out.print("given num is prime");<br /> }<br /> }<br /><br />}anonymoushttps://www.blogger.com/profile/11166353202229387268noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-22911134622535122292018-09-28T21:46:36.591-07:002018-09-28T21:46:36.591-07:00import java.util.Scanner;
public class Main{
...import java.util.Scanner;<br />public class Main{<br /><br /> public static void main(String []args)<br /> {<br /> int a;<br /> boolean flag=false;<br /> System.out.println("enter number:");<br /> Scanner sc=new Scanner(System.in);<br /> a=sc.nextInt();<br /> for(int i=2;i<=a/2;i++)<br /> {<br /> if(a%i==0)<br /> {<br /> flag=true;<br /> break;<br /> }<br /> }<br /> if(!flag)<br /> System.out.println("is prime");<br /> else<br /> System.out.println("is not prime");<br /> }<br /> <br /><br />}Navakishorehttps://www.blogger.com/profile/17343621217103187496noreply@blogger.comtag:blogger.com,1999:blog-694855878384792308.post-37729738537301053632018-08-21T08:01:47.200-07:002018-08-21T08:01:47.200-07:00import java.util.*;
import java.io.*;
import java....import java.util.*;<br />import java.io.*;<br />import java.math.*;<br /><br />class Prime<br />{<br />public static void main(String args[])<br />{<br />Scanner sc=new Scanner(System.in);<br />int i,n,j,k=0;<br /><br />System.out.println("Enter any Number:");<br />n=sc.nextInt();<br /><br />j=(int)Math.sqrt(n);<br /><br />for(i=2;i<=j;i++)<br />{<br /> if(n%i==0)<br />{<br /> k++;<br />}<br />else <br /> ;<br />}<br />if(k==0)<br />System.out.println("Prime Number");<br />else<br />System.out.println("Not a Prime Number"); <br />}<br />}Wishing_Scriptshttps://www.blogger.com/profile/07987969670070949583noreply@blogger.com