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 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

User · Answer

Using BufferedReader -   StringTokenizer st   new StringTokenizer buf readLine      while st hasMoreTokens        arr i      Integer parseInt st nextToken

User · Answer

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

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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  lt  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

User · Answer

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  quot   s  quot                     for  int i   0  i  lt  strs length  i          a i    Integer parseInt strs i

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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 lt n i         a i    scan nextInt

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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

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Java 8   BufferedReader in   new BufferedReader new InputStreamReader System in    int arr     Arrays stream in readLine   split       mapToInt Integer  parseInt  toArray

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Scanner has a method called hasNext         Scanner scanner   new Scanner System in        while scanner hasNext                  System out println scanner nextInt

User · Answer

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  lt  3  i          integers i    sc nextInt

User · Answer

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 lt Integer gt  l   new LinkedList lt  gt        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

User · Answer

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  lt  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  lt  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  lt  stringsArray length  i                  intArray i    Integer parseInt stringsArray i

User · Answer

This works fine       int a   nextInt    int b   nextInt    int c   nextInt     Or you can read them in a loop

User · Answer

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 gt 0                          for i 0  i lt 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 lt n  i                   a i    Integer parseInt strs i      Converting String Integer to Integer          System out println a i

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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  lt  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

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i know it s old discuss    i tested below code it s worked   String day        day   sc next     days i    Integer parseInt day

User · Answer

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

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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

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

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