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Taking integers as input from console and storing them in an array

When I am trying to write the following code, the computer takes several inputs. But what I want is it should take only one line as an input and save all the integers in that line in an array. Can you help me with this please?
import java.util.*;
class InputInteger{
public static void main(String args[]){
Scanner input=new Scanner(System.in);
int[] array=new int[20];
int i=0;
while(input.hasNext()){
array[i]=input.nextInt();
i++;
}
input.close();
}
}

But what I want is it should take only one line as an input and save all the integers in that line in an array.
First, I urge you not to close() a Scanner that you have created around System.in. That's a global, and close()ing can cause you all kinds of issues later (because you can't reopen it). As for reading a single line of input and splitting int values into an array, you could do use Scanner.nextLine() and something like
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
if (input.hasNextLine()) {
String line = input.nextLine();
String[] arr = line.split("\\s+");
int[] vals = new int[arr.length];
for (int i = 0; i < arr.length; i++) {
vals[i] = Integer.parseInt(arr[i]);
}
System.out.println(Arrays.toString(vals));
}
}
Edit Based on your comment,
String line = "1 31 41 51";
String[] arr = line.split("\\s+");
int[] vals = new int[arr.length];
for (int i = 0; i < arr.length; i++) {
vals[i] = Integer.parseInt(arr[i]);
}
System.out.println(Arrays.toString(vals));
Output is
[1, 31, 41, 51]
If you need to handle errors, I suggest you use a List like
List<Integer> al = new ArrayList<>();
for (int i = 0; i < arr.length; i++) {
try {
al.add(Integer.parseInt(arr[i]));
} catch (NumberFormatException nfe) {
}
}
// You could now print the List
System.out.println(al);
// And if you must have an `int[]` copy it like.
int[] vals = new int[al.size()];
for (int i = 0; i < al.size(); i++) {
vals[i] = al.get(i);
}
System.out.println(Arrays.toString(vals));

You can capture the input as String and use for loop to process it:
Scanner input=new Scanner(System.in);
int[] array=new int[20];
String numbers = input.nextLine();
for(int i = 0 ; i<numbers.length() ; i++){
array[i]=Character.getNumericValue(numbers.charAt(i));
}
But in this case, the number of digits must be not exceed your array size, which is 20. Or else it will throw ArrayIndexOutOfBound Exception. You may want to do Exception handling on this.
Or to avoid that, you can declare your array with size equal to length of the input:
int[] array=new int[numbers.length()];
See the demo here

Scanner input = new Scanner(System.in);
ArrayList<Integer> nums = new ArrayList<Integer>();
boolean repeat = true;
while (repeat) {
System.out
.print("Enter a bunch of integers seperated by spaces, or 'q' to quit: ");
String line = input.nextLine();
if (line.equals("q"))
repeat = false;
else {
String[] numbers = line.split("\\s+");
for (String num : numbers) {
if (!nums.contains(num))
nums.add(Integer.parseInt(num));
}
}
}
for (Integer i : nums) {
System.out.println(i);
}
input.close();

How to read multiple integer values from one line in Java using BufferedReader object?

I am using BufferedReader class to read inputs in my Java program.
I want to read inputs from a user who can enter multiple integer data in single line with space.
I want to read all these data in an integer array.
Input format-
the user first enters how many numbers he/she want to enter
And then multiple integer values in the next single line-
INPUT:
5
2 456 43 21 12
Now, I read input using an object (br) of BufferedReader
int numberOfInputs = Integer.parseInt(br.readLine());
Next, I want to read next line inputs in an array
int a[] = new int[n];
But we cannot read using this technique
for(int i=0;i<n;i++)
{
a[i]=Integer.parseInt(br.readLine()); //won't work
}
So, is there any solution to my problem or we can't just read multiple integers from one line using BufferedReader objects
Because using Scanner object we can read this type of input
for(int i=0;i<n;i++)
{
a[i]=in.nextInt(); //will work..... 'in' is object of Scanner class
}

Try the next:
int a[] = new int[n];
String line = br.readLine(); // to read multiple integers line
String[] strs = line.trim().split("\\s+");
for (int i = 0; i < n; i++) {
a[i] = Integer.parseInt(strs[i]);
}

Late to the party but you can do this in one liner in Java 8 using streams.
InputStreamReader isr= new InputStreamReader();
BufferedReader br= new BufferedReader(isr);
int[] input = Arrays.stream(br.readLine().split("\\s+")).mapToInt(Integer::parseInt).toArray();

If you want to read integers and you didn't know number of integers
String[] integersInString = br.readLine().split(" ");
int a[] = new int[integersInString.length];
for (int i = 0; i < integersInString.length; i++) {
a[i] = Integer.parseInt(integersInString[i]);
}

Integer.parseInt(br.readLine()) -> Reads a whole line and then converts it to Integers.
scanner.nextInt() -> Reads every single token one by one within a single line then tries to convert it to integer.
String[] in = br.readLine().trim().split("\\s+");
// above code reads the whole line, trims the extra spaces
// before or after each element until one space left,
// splits each token according to the space and store each token as an element of the string array.
for(int i = 0; i < n; i++)
arr[i] = Integer.parseInt(in[i]);
// Converts each element in the string array as an integer and stores it in an integer array.

import java.io.*;
public class HelloWorld{
public static void main(String []args){
int i;
System.out.println("enter the array element");
InputStreamReader isr= new InputStreamReader();
BufferedReader ib= new BufferedReader(isr);
int a[]=new int [5];
for(i=0;i<5;i++)
{
a[i]= Integer.parseInt(ib.readLine(a[i]));
}
for(i=0;i<5;i++)
{
System.out.println(a[i]);
}
}
}

I use this code for List:
List<Integer> numbers = Stream.of(reader.readLine().split("\\s+")).map(Integer::valueOf).collect(Collectors.toList());
And it is almost the same for array:
int[] numbersArray = Arrays.stream(reader.readLine().split("\\s+")).mapToInt(Integer::valueOf).toArray();

You can use StringTokenizer class of java.util package. The StringTokenizer class allows an application to break a string into tokens. You can use this tokens using nextToken() method of StringTokenizer class.
You can use following constructor of StringTokenizer:
StringTokenizer(String str, String delimiter);
you can use space(" ") as delemeter.
int a[] = new int[N];
StringTokenizer st = new StringTokenizer(br.readLine() , " ");
for(int i=0 ; i<N ; i++) {
a[i] = Integer.parseInt(st.nextToken());
}

Well as you mentioned there are two lines-
First line takes number of integers and second takes that many number
INPUT: 5 2 456 43 21 12
So to address this and covert it into array -
String[] strs = inputData.trim().split("\\s+"); //String with all inputs 5 2 456 43 21 12
int n= Integer.parseInt(strs[0]); //As you said first string contains the length
int a[] = new int[n]; //Initializing array of that length
for (int i = 0; i < n; i++)
{
a[i] = Integer.parseInt(strs[i+1]); // a[0] will be equal to a[1] and so on....
}

i/p:34 54
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer st = new StringTokenizer(br.readLine()," ");
for(int i=0;i<st.countTokens();i++){
a=Integer.parseInt(st.nextToken());
b=Integer.parseInt(st.nextToken());
}
//For fast input output for one line

How to read multiple Integer values from a single line of input in Java?

I am working on a program and I want to allow a user to enter multiple integers when prompted. I have tried to use a scanner but I found that it only stores the first integer entered by the user. For example:
Enter multiple integers: 1 3 5
The scanner will only get the first integer 1. Is it possible to get all 3 different integers from one line and be able to use them later? These integers are the positions of data in a linked list I need to manipulate based on the users input. I cannot post my source code, but I wanted to know if this is possible.

I use it all the time on hackerrank/leetcode
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String lines = br.readLine();
String[] strs = lines.trim().split("\\s+");
for (int i = 0; i < strs.length; i++) {
a[i] = Integer.parseInt(strs[i]);
}

Try this
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
while (in.hasNext()) {
if (in.hasNextInt())
System.out.println(in.nextInt());
else
in.next();
}
}
By default, Scanner uses the delimiter pattern "\p{javaWhitespace}+" which matches at least one white space as delimiter. you don't have to do anything special.
If you want to match either whitespace(1 or more) or a comma, replace the Scanner invocation with this
Scanner in = new Scanner(System.in).useDelimiter("[,\\s+]");

You want to take the numbers in as a String and then use String.split(" ") to get the 3 numbers.
String input = scanner.nextLine(); // get the entire line after the prompt
String[] numbers = input.split(" "); // split by spaces
Each index of the array will hold a String representation of the numbers which can be made to be ints by Integer.parseInt()

Scanner has a method called hasNext():
Scanner scanner = new Scanner(System.in);
while(scanner.hasNext())
{
System.out.println(scanner.nextInt());
}

If you know how much integers you will get, then you can use nextInt() method
For example
Scanner sc = new Scanner(System.in);
int[] integers = new int[3];
for(int i = 0; i < 3; i++)
{
integers[i] = sc.nextInt();
}

Java 8
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
int arr[] = Arrays.stream(in.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();

Here is how you would use the Scanner to process as many integers as the user would like to input and put all values into an array. However, you should only use this if you do not know how many integers the user will input. If you do know, you should simply use Scanner.nextInt() the number of times you would like to get an integer.
import java.util.Scanner; // imports class so we can use Scanner object
public class Test
{
public static void main( String[] args )
{
Scanner keyboard = new Scanner( System.in );
System.out.print("Enter numbers: ");
// This inputs the numbers and stores as one whole string value
// (e.g. if user entered 1 2 3, input = "1 2 3").
String input = keyboard.nextLine();
// This splits up the string every at every space and stores these
// values in an array called numbersStr. (e.g. if the input variable is
// "1 2 3", numbersStr would be {"1", "2", "3"} )
String[] numbersStr = input.split(" ");
// This makes an int[] array the same length as our string array
// called numbers. This is how we will store each number as an integer
// instead of a string when we have the values.
int[] numbers = new int[ numbersStr.length ];
// Starts a for loop which iterates through the whole array of the
// numbers as strings.
for ( int i = 0; i < numbersStr.length; i++ )
{
// Turns every value in the numbersStr array into an integer
// and puts it into the numbers array.
numbers[i] = Integer.parseInt( numbersStr[i] );
// OPTIONAL: Prints out each value in the numbers array.
System.out.print( numbers[i] + ", " );
}
System.out.println();
}
}

There is more than one way to do that but simple one is using String.split(" ")
this is a method of String class that separate words by a spacial character(s) like " " (space)
All we need to do is save this word in an Array of Strings.
Warning : you have to use scan.nextLine(); other ways its not going to work(Do not use scan.next();
String user_input = scan.nextLine();
String[] stringsArray = user_input.split(" ");
now we need to convert these strings to Integers. create a for loop and convert every single index of stringArray :
for (int i = 0; i < stringsArray.length; i++) {
int x = Integer.parseInt(stringsArray[i]);
// Do what you want to do with these int value here
}
Best way is converting the whole stringArray to an intArray :
int[] intArray = new int[stringsArray.length];
for (int i = 0; i < stringsArray.length; i++) {
intArray[i] = Integer.parseInt(stringsArray[i]);
}
now do any proses you want like print or sum or... on intArray
The whole code will be like this :
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String user_input = scan.nextLine();
String[] stringsArray = user_input.split(" ");
int[] intArray = new int[stringsArray.length];
for (int i = 0; i < stringsArray.length; i++) {
intArray[i] = Integer.parseInt(stringsArray[i]);
}
}
}

This works fine ....
int a = nextInt();
int b = nextInt();
int c = nextInt();
Or you can read them in a loop

Using this on many coding sites:
CASE 1: WHEN NUMBER OF INTEGERS IN EACH LINE IS GIVEN
Suppose you are given 3 test cases with each line of 4 integer inputs separated by spaces 1 2 3 4, 5 6 7 8 , 1 1 2 2
int t=3,i;
int a[]=new int[4];
Scanner scanner = new Scanner(System.in);
while(t>0)
{
for(i=0; i<4; i++){
a[i]=scanner.nextInt();
System.out.println(a[i]);
}
//USE THIS ARRAY A[] OF 4 Separated Integers Values for solving your problem
t--;
}
CASE 2: WHEN NUMBER OF INTEGERS in each line is NOT GIVEN
Scanner scanner = new Scanner(System.in);
String lines=scanner.nextLine();
String[] strs = lines.trim().split("\\s+");
Note that you need to trim() first: trim().split("\\s+") - otherwise, e.g. splitting a b c will emit two empty strings first
int n=strs.length; //Calculating length gives number of integers
int a[]=new int[n];
for (int i=0; i<n; i++)
{
a[i] = Integer.parseInt(strs[i]); //Converting String_Integer to Integer
System.out.println(a[i]);
}

created this code specially for the Hacker earth exam
Scanner values = new Scanner(System.in); //initialize scanner
int[] arr = new int[6]; //initialize array
for (int i = 0; i < arr.length; i++) {
arr[i] = (values.hasNext() == true ? values.nextInt():null);
// it will read the next input value
}
/* user enter = 1 2 3 4 5
arr[1]= 1
arr[2]= 2
and soo on
*/

It's working with this code:
Scanner input = new Scanner(System.in);
System.out.println("Enter Name : ");
String name = input.next().toString();
System.out.println("Enter Phone # : ");
String phone = input.next().toString();

A simple solution can be to consider the input as an array.
Scanner sc = new Scanner(System.in);
int n = sc.nextInt(); //declare number of integers you will take as input
int[] arr = new int[n]; //declare array
for(int i=0; i<arr.length; i++){
arr[i] = sc.nextInt(); //take values
}

You're probably looking for String.split(String regex). Use " " for your regex. This will give you an array of strings that you can parse individually into ints.

Better get the whole line as a string and then use StringTokenizer to get the numbers (using space as delimiter ) and then parse them as integers . This will work for n number of integers in a line .
Scanner sc = new Scanner(System.in);
List<Integer> l = new LinkedList<>(); // use linkedlist to save order of insertion
StringTokenizer st = new StringTokenizer(sc.nextLine(), " "); // whitespace is the delimiter to create tokens
while(st.hasMoreTokens()) // iterate until no more tokens
{
l.add(Integer.parseInt(st.nextToken())); // parse each token to integer and add to linkedlist
}

Using BufferedReader -
StringTokenizer st = new StringTokenizer(buf.readLine());
while(st.hasMoreTokens())
{
arr[i++] = Integer.parseInt(st.nextToken());
}

When we want to take Integer as inputs
For just 3 inputs as in your case:
import java.util.Scanner;
Scanner scan = new Scanner(System.in);
int a,b,c;
a = scan.nextInt();
b = scan.nextInt();
c = scan.nextInt();
For more number of inputs we can use a loop:
import java.util.Scanner;
Scanner scan = new Scanner(System.in);
int a[] = new int[n]; //where n is the number of inputs
for(int i=0;i<n;i++){
a[i] = scan.nextInt();
}

This method only requires users to enter the "return" key once after they have finished entering numbers:
It also skips special characters so that the final array will only contains integers
ArrayList<Integer> nums = new ArrayList<>();
// User input
Scanner sc = new Scanner(System.in);
String n = sc.nextLine();
if (!n.isEmpty()) {
String[] str = n.split(" ");
for (String s : str) {
try {
nums.add(Integer.valueOf(s));
} catch (NumberFormatException e) {
System.out.println(s + " cannot be converted to Integer, skipping...");
}
}
}

//Get user input as a 1 2 3 4 5 6 .... and then some of the even or odd number like as 2+4 = 6 for even number
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int evenSum = 0;
int oddSum = 0;
while (n > 0) {
int last = n % 10;
if (last % 2 == 0) {
evenSum += last;
} else {
oddSum += last;
}
n = n / 10;
}
System.out.println(evenSum + " " + oddSum);
}
}

if ur getting nzec error, try this:
try{
//your code
}
catch(Exception e){
return;
}

i know it's old discuss :) i tested below code it's worked
`String day = "";
day = sc.next();
days[i] = Integer.parseInt(day);`

Java Take String input from console

I was trying to take string input in java. My input should be like this
3
1,1,bugs#bunny.com,123 Sesame St.,New York,NY,10011,12345689010
1,2,bugs#bunny.com,123 Sesame St.,New York,NY,10011,12345689010
1,3,bugs#bunny.com,123 Sesame St.,New York,NY,10011,12345689010
So, I tried this
Scanner in = new Scanner(System.in);
int TotalNumber = in.nextInt();
String[] Data = new String[TotalNumber];
for (int Counter = 0; Counter < TotalNumber; Counter++) {
Data[Counter] = in.next();
}
in.close();
for (int counter = 0; counter < Data.length; counter++) {
System.out.println(Data[counter]);
}
My output is showing this
1,1,bugs#bunny.com,123
Sesame
St.,New
What is my problem ? How take input string line properly ?
Update
I found my solution at here Scanner issue when using nextLine after nextXXX

next() breaks at a whitespace. Instead, you should use nextLine() to input the entire line to your string:
int TotalNumber = in.nextInt();
String[] Data = new String[TotalNumber];
for (int Counter = 0; Counter < TotalNumber; Counter++) {
Data[Counter] = in.nextLine();
}

Try with Data[Counter] = in.nextLine();

What about:
import java.util.Scanner;
import java.lang.String;
public class Test
{
public static void main(String[] args)
{
char[] sArray;
Scanner scan = new Scanner(System.in);
System.out.print("Enter a Palindrome : ");
String s = scan.nextLine();
s = s.replaceAll("\\s+", "");
sArray = new char[s.length()];
for(int i = 0; i < s.length(); i++)
{
sArray[i] = s.charAt(i);
System.out.print(sArray[i]);
}
}
}

Try this (Mureinik modified code)..
int TotalNumber = in.nextInt();
in.nextLine();
String[] Data = new String[TotalNumber];
for (int Counter = 0; Counter < TotalNumber; Counter++) {
Data[Counter] = in.nextLine();
}
You need a nextLine() after taking the int because you will press enter after taking int and that enter is read by nextLine() in the Data[0].

How does nextLine work with scanner?

I am trying to split "sisestus" into different words by using space as a separator, but by just using sc.next() doesn't allow me to enter a string with spaces so i read that i should use .nextLine(), but it doesn't work at all. How do i solve it?
public class Sisestamine {
int read;
int veerud;
double Maatriks[][];
java.util.Scanner sc = new java.util.Scanner(System.in);
Sisestamine() {
System.out.println("Enter matrix dimensions (format NxM)");
String[] abi = sc.next().split("x");
this.read = Integer.parseInt(abi[0]);
this.veerud = Integer.parseInt(abi[1]);
this.Maatriks = new double[read][veerud];
System.out.println("Enter the matrix: (x x x x etc..)");
for (int i = 0; i < read; i++) {
String sisestus = sc.next();
//String sisestus = sc.nextLine();
abi = sisestus.split(" ");
System.out.print(abi);
for (int j = 0; j < abi.length; j++) {
this.Maatriks[i][j] = Double.parseDouble(abi[j]);
}
}
}
}

Your problem could be because you're using sc.next() at one part of your program and then sc.nextLine() later, and the second call swallows the end of line (EOL) token that was left hanging from the prior call to next(). A solution is to use sc.nextLine() for all invocations. In other words, change all sc.next() to sc.nextLine().