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

Question

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 intege

Answer 1

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]);
      }
  

Answer 2

i know it's old discuss :) i tested below code it's worked

`String day = "";
 day = sc.next();
 days[i] = Integer.parseInt(day);`

Answer 3

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();
}

Answer 4

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();    
}

Answer 5

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

    }