I would like to write the result of any calculation on the same line where the user enters the input (scanner).
For a better understanding of my question -
Code example:
Scanner scanner = new Scanner(System.in);
int num1 = scanner.nextInt(); // num = 1
String op = scanner.next(); // operator = + // I know this line is being ignored.
// It's just to keep a line of reasoning.
int num2 = scanner.nextInt(); // num = 2
System.out.print(" = " + num1+num2);
Output from IDE:
1 + 2
= 3
Desired output:
1 + 2 = 3
I want my program to input int values from the user on the same line (e.g. 12345), and display the output with spaces between the int values(1 2 3 4 5). Please help.
{
Scanner input = new Scanner(System.in);
System.out.print("Enter Number: ");
int num = input.nextInt();
String van = toString(num);
System.out.println("The Numbers are: " + van);
}
There are many ways, for example:
Solution 1
You can use for example String.join from Java8+, like so :
String van = String.valueOf(num);
System.out.println(String.join(" ", van.split("")));
Outputs
1 2 3 4 5
Solution 2
You can use replaceAll like this :
System.out.println(van.replaceAll(".", "$ ").trim());
for(int i = 0; i < van.length(); i++)
System.out.print(van.charAt(i) + " ");
The solution can be following
Scanner input = new Scanner(System.in);
System.out.print("Enter Number: ");
int num = input.nextInt();
String value = String.valueOf(num);
String newString = "";
for (int i = 0; i < value.length(); i++) {
newString = newString + value.charAt(i) + " ";
}
System.out.println("newString=>" + newString.trim());
I have to make a method to print out the elements in an array, separated by ‘‘|’’
#param values, an array of integers.
Essentially its suppose to take user input, and then from there separate it with |. This is what I have so far. Any help chaps?
int [] scans = new int [3];
System.out.println("Enter 4 Numbers into the array: " );
Scanner scanner = new Scanner(System.in);
int s = scanner.nextInt();
for (int i = 0; i < scans.length; i++)
{
scans [i] = scanner.nextInt();
}
First, you're ignoring the first input number by assigning it to s, but you never use that thereafter. For the joining problem, you can use a stream. Below will ask the user to input 3 numbers, save them to your int[3] and output it joined by |
int [] scans = new int[3];
System.out.println("Enter 3 Numbers into the array: " );
Scanner scanner = new Scanner(System.in);
for (int i = 0; i < scans.length; i++) {
scans [i] = scanner.nextInt();
}
String joined = Arrays.stream(scans)
.mapToObj(String::valueOf)
.collect(Collectors.joining("|"));
System.out.println(joined);
Here is a solution that might be easier to understand without using the mapToObj solution #baao used (which is fine, but maybe harder to understand if your new to Java).
First of all if you want to store 4 numbers in the array, then your array should hold 4 not 3 elements. Another trick you can use is to create a prefix variable that is used to prepend each number in a loop over the values in the array. After the first iteration the prefix should be set to your separator variable.
You can see it working here: https://ideone.com/QCNPZQ
int [] scans = new int[4];
System.out.println("Enter 4 numbers into the array: " );
Scanner scanner = new Scanner(System.in);
for (int i=0; i<scans.length; i++) {
scans [i] = scanner.nextInt();
}
String prefix = "";
String result = "";
for(int i=0; i<scans.length; i++){
result = result + prefix + scans[i];
prefix = "|";
}
System.out.println(result);
I'm trying to grab 3 strings from the user.
The issue I'm running into at the moment is that the scanner never ends/never stores the first user input value? With the limited amount of research I've done so far it appears that the scanner method has some intricacies that lie far beyond the cover.
My current code is below, followed by the complete method. Any sort of explanation would be highly appreciated. Thank you!
Code pertaining to question:
//prompt user for array values by row
System.out.println("Enter matrix values by row: ");
userInput[0] = in.nextLine();
userInput[1] = in.nextLine();
userInput[2] = in.nextLine();
Complete method:
public static double[][] setArray()
{
//initiate variables
String stringValue = "";
double doubleValue = 0;
//instantiate string array for user input values
String[] userInput = new String[3];
//instantiate return array
double[][] array = new double[3][4];
//prompt user for array values by row
System.out.println("Enter matrix values by row: ");
userInput[0] = in.nextLine();
userInput[1] = in.nextLine();
userInput[2] = in.nextLine();
//stop each scanner
int valueCounter = 0;
for(int eachString = 0; eachString < 3; eachString++)
{
for(int index = 0; index < userInput[eachString].length(); index++)
{
//exception handling
//if string does not contain a space, period, or valid digit
while(userInput[eachString].charAt(index) != ' '
&& userInput[eachString].charAt(index) < '0'
&& userInput[eachString].charAt(index) > '9'
&& userInput[eachString].charAt(index) != '.')
{
System.out.println("Invalid input. Digits must be in integer"
+ " or double form. (i.e. 4 5.0 2.3 9)");
System.out.println("Re-enter given matrix value");
userInput[eachString] = in.nextLine();
}
}
//given string is valid at this point//
//for each index in string value
for(int eachIndex = 0; eachIndex < userInput[eachString].length(); eachIndex++)
{
//while value != ' '... += string... if value == ' ' stop loop
while(userInput[eachString].charAt(eachIndex) != ' ')
{
stringValue += userInput[eachString].charAt(eachIndex);
}
doubleValue = Double.valueOf(stringValue);
array[eachString][valueCounter] = doubleValue;
valueCounter++;//array[0-2][0-3 (valueCounter)]
stringValue = "";//clear string
}
}
return array;
}
You would just want to break up the scanner to read 1 number at a time and then ask for the second number and then read it in and then ask for the third number.
Or you could have them provide the 3 numbers divided by a space or something and read it in as a string and split the string per each space and parse to each userInput.
I would so the latter, it would look something like this:
System.out.println("Enter matrix values by row: ");
String temp = in.nextLine();
String[] tempArray = temp.split("\\s+");
userInput[0] = tempArray[0];
userInput[1] = tempArray[1];
userInput[2] = tempArray[2];
Obviously error checking needs to happen. But this should work for you.
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);`