How can I make my code more efficient on reading prime number, and continue on looping when 0 or 1 is input
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import java.util.*;
public class PrimeNumber {
private static ArrayList<Integer> listOfPrime = new ArrayList<Integer>();
public static void main(String args) {
Scanner userInput = new Scanner(System.in);
System.out.print("Please enter a number to checked the list of prime number > ");
//Request user to input number.
String input = userInput.nextLine();
int number = 0;
boolean check = false;
//Check if integer entered is it integer
while(check != true) {
try {
// if input can be parse into integer, shows that its number so can change check into true to exit the while loop
number = Integer.parseInt(input);
check = true;
}
catch(NumberFormatException e) {
System.out.println("Please enter numbers only > ");
input = userInput.nextLine();
}
}
//Check if input enter is 0 or 1, as prime number cannot be those.
if(number < 2) {
System.out.println("Prime number cannot be 0 or 1");
}else {
checkPrime(number);
}
}
//Check for all prime numbers within the number user input.
private static void checkPrime(int input) {
boolean primeValidation = true;
//first for loop to check from small to biggest integer in the input
for(int i = 1; i <= input;i++) {
if(i !=1) {
//Second for loop to check from prime number in the small to big number.
//If the number i is 2 or 3, the loop will exit and add into the list as the default is prime, and no option changes it to not prime number.
for(int x = 2; x < i ; x++) {
if(i%x == 0) {
//If the number is divisable by any number to 0, set it to not prime.
primeValidation = false;
}
}
}
`//if the input is either 0 or 1 set it to false and 0 and 1 is not prime
`else {
primeValidation = false;
}
if(primeValidation == true) {
listOfPrime.add(i);
}else {
primeValidation = true;
}
}
System.out.println("The list of prime numbers of the number " + input + " are "+listOfPrime);
}
}
java
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import java.util.*;
public class PrimeNumber {
private static ArrayList<Integer> listOfPrime = new ArrayList<Integer>();
public static void main(String args) {
Scanner userInput = new Scanner(System.in);
System.out.print("Please enter a number to checked the list of prime number > ");
//Request user to input number.
String input = userInput.nextLine();
int number = 0;
boolean check = false;
//Check if integer entered is it integer
while(check != true) {
try {
// if input can be parse into integer, shows that its number so can change check into true to exit the while loop
number = Integer.parseInt(input);
check = true;
}
catch(NumberFormatException e) {
System.out.println("Please enter numbers only > ");
input = userInput.nextLine();
}
}
//Check if input enter is 0 or 1, as prime number cannot be those.
if(number < 2) {
System.out.println("Prime number cannot be 0 or 1");
}else {
checkPrime(number);
}
}
//Check for all prime numbers within the number user input.
private static void checkPrime(int input) {
boolean primeValidation = true;
//first for loop to check from small to biggest integer in the input
for(int i = 1; i <= input;i++) {
if(i !=1) {
//Second for loop to check from prime number in the small to big number.
//If the number i is 2 or 3, the loop will exit and add into the list as the default is prime, and no option changes it to not prime number.
for(int x = 2; x < i ; x++) {
if(i%x == 0) {
//If the number is divisable by any number to 0, set it to not prime.
primeValidation = false;
}
}
}
`//if the input is either 0 or 1 set it to false and 0 and 1 is not prime
`else {
primeValidation = false;
}
if(primeValidation == true) {
listOfPrime.add(i);
}else {
primeValidation = true;
}
}
System.out.println("The list of prime numbers of the number " + input + " are "+listOfPrime);
}
}
java
New contributor
Welcome to Code Review. Please fix your indentation. The easiest way to post core is to paste it into the question editor, highlight it, and press Ctrl-K to mark it as a code block. Also tell us what the code accomplishes — see How to Ask.
– 200_success
39 mins ago
add a comment |
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import java.util.*;
public class PrimeNumber {
private static ArrayList<Integer> listOfPrime = new ArrayList<Integer>();
public static void main(String args) {
Scanner userInput = new Scanner(System.in);
System.out.print("Please enter a number to checked the list of prime number > ");
//Request user to input number.
String input = userInput.nextLine();
int number = 0;
boolean check = false;
//Check if integer entered is it integer
while(check != true) {
try {
// if input can be parse into integer, shows that its number so can change check into true to exit the while loop
number = Integer.parseInt(input);
check = true;
}
catch(NumberFormatException e) {
System.out.println("Please enter numbers only > ");
input = userInput.nextLine();
}
}
//Check if input enter is 0 or 1, as prime number cannot be those.
if(number < 2) {
System.out.println("Prime number cannot be 0 or 1");
}else {
checkPrime(number);
}
}
//Check for all prime numbers within the number user input.
private static void checkPrime(int input) {
boolean primeValidation = true;
//first for loop to check from small to biggest integer in the input
for(int i = 1; i <= input;i++) {
if(i !=1) {
//Second for loop to check from prime number in the small to big number.
//If the number i is 2 or 3, the loop will exit and add into the list as the default is prime, and no option changes it to not prime number.
for(int x = 2; x < i ; x++) {
if(i%x == 0) {
//If the number is divisable by any number to 0, set it to not prime.
primeValidation = false;
}
}
}
`//if the input is either 0 or 1 set it to false and 0 and 1 is not prime
`else {
primeValidation = false;
}
if(primeValidation == true) {
listOfPrime.add(i);
}else {
primeValidation = true;
}
}
System.out.println("The list of prime numbers of the number " + input + " are "+listOfPrime);
}
}
java
New contributor
import java.util.*;
public class PrimeNumber {
private static ArrayList<Integer> listOfPrime = new ArrayList<Integer>();
public static void main(String args) {
Scanner userInput = new Scanner(System.in);
System.out.print("Please enter a number to checked the list of prime number > ");
//Request user to input number.
String input = userInput.nextLine();
int number = 0;
boolean check = false;
//Check if integer entered is it integer
while(check != true) {
try {
// if input can be parse into integer, shows that its number so can change check into true to exit the while loop
number = Integer.parseInt(input);
check = true;
}
catch(NumberFormatException e) {
System.out.println("Please enter numbers only > ");
input = userInput.nextLine();
}
}
//Check if input enter is 0 or 1, as prime number cannot be those.
if(number < 2) {
System.out.println("Prime number cannot be 0 or 1");
}else {
checkPrime(number);
}
}
//Check for all prime numbers within the number user input.
private static void checkPrime(int input) {
boolean primeValidation = true;
//first for loop to check from small to biggest integer in the input
for(int i = 1; i <= input;i++) {
if(i !=1) {
//Second for loop to check from prime number in the small to big number.
//If the number i is 2 or 3, the loop will exit and add into the list as the default is prime, and no option changes it to not prime number.
for(int x = 2; x < i ; x++) {
if(i%x == 0) {
//If the number is divisable by any number to 0, set it to not prime.
primeValidation = false;
}
}
}
`//if the input is either 0 or 1 set it to false and 0 and 1 is not prime
`else {
primeValidation = false;
}
if(primeValidation == true) {
listOfPrime.add(i);
}else {
primeValidation = true;
}
}
System.out.println("The list of prime numbers of the number " + input + " are "+listOfPrime);
}
}
java
java
New contributor
New contributor
edited 33 mins ago
πάντα ῥεῖ
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3,87531327
New contributor
asked 43 mins ago
Hau Jia Hung
1
1
New contributor
New contributor
Welcome to Code Review. Please fix your indentation. The easiest way to post core is to paste it into the question editor, highlight it, and press Ctrl-K to mark it as a code block. Also tell us what the code accomplishes — see How to Ask.
– 200_success
39 mins ago
add a comment |
Welcome to Code Review. Please fix your indentation. The easiest way to post core is to paste it into the question editor, highlight it, and press Ctrl-K to mark it as a code block. Also tell us what the code accomplishes — see How to Ask.
– 200_success
39 mins ago
Welcome to Code Review. Please fix your indentation. The easiest way to post core is to paste it into the question editor, highlight it, and press Ctrl-K to mark it as a code block. Also tell us what the code accomplishes — see How to Ask.
– 200_success
39 mins ago
Welcome to Code Review. Please fix your indentation. The easiest way to post core is to paste it into the question editor, highlight it, and press Ctrl-K to mark it as a code block. Also tell us what the code accomplishes — see How to Ask.
– 200_success
39 mins ago
add a comment |
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Hau Jia Hung is a new contributor. Be nice, and check out our Code of Conduct.
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Hau Jia Hung is a new contributor. Be nice, and check out our Code of Conduct.
Hau Jia Hung is a new contributor. Be nice, and check out our Code of Conduct.
Hau Jia Hung is a new contributor. Be nice, and check out our Code of Conduct.
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Welcome to Code Review. Please fix your indentation. The easiest way to post core is to paste it into the question editor, highlight it, and press Ctrl-K to mark it as a code block. Also tell us what the code accomplishes — see How to Ask.
– 200_success
39 mins ago