This question already has answers here:
Java String Concatenation with + operator
(5 answers)
Closed 5 months ago.
How can I find the value of an array and its number position using for Loop?
import java.util.Scanner;
public class prac{
public static void main(String[] args) {
int n, element, pos=0, i;
Scanner sc = new Scanner(System.in);
System.out.println("Enter array size [1-100]: ");
n = sc.nextInt();
int[] a = new int[100];
System.out.println("Enter array elements: ");
for(i=0; i<n; i++) {
a[i]=sc.nextInt();
}
System.out.println("Enter element to search: ");
element=sc.nextInt();
for (i=0; i<n; i++) {
if (a[i]==element) {
System.out.println(element+ " found at position "+ i+1);
}
}
System.out.println(element+"not found");
When I run this it gives me this output:Enter array size [1-100]:
3
Enter array elements:
1
2
3
Enter element to search:
3
3 found at position 21
What kind of solution should I do to fix this?
First problem is:
In the print command, when you write i+1 it is string.
For example if i = 5, the output is 51, but you mean an integer.
Thus write (i+1), So:
System.out.println(element + " found at position "+ (i+1));
Second problem is that your second print command is out of for loop. so it run anyway. One of the solution is that you can use boolean variable.
Try this:
import java.util.Scanner;
public class prac {
public static void main(String[] args) {
int n, element, pos = 0, i;
boolean flag = false;
Scanner sc = new Scanner(System.in);
System.out.println("Enter array size [1-100]: ");
n = sc.nextInt();
int[] a = new int[n];
System.out.println("Enter array elements: ");
for(i = 0; i < n; i++)
a[i] = sc.nextInt();
System.out.println("Enter element to search: ");
element = sc.nextInt();
for (i = 0; i < n; i++) {
if (a[i] == element) {
System.out.println(element + " found at position " + (i+1));
flag = true;
}
}
if(!flag) // flag == false
System.out.println(element + "not found");
}
}
Good luck.
This question already has answers here:
Scanner is skipping nextLine() after using next() or nextFoo()?
(24 answers)
Closed 4 years ago.
I was setting up a small app that asks a user to determine the array size and then populate it. The used "for" loop skips the index 0; but I'm uncertain why.
If you run this code with 1 as the array size it skips over the user inputting the first word.
The issue is certainly on the for-loop but it is so simple that I don't see it.
Thanks!
import java.util.Scanner;
public class WordRandomizerAdvanced {
public static void main(String[] args) {
int arrayDimesion;
Scanner sc = new Scanner(System.in);
System.out.println("****************************************************");
System.out.println("******** Welcome to Word Randomizer ADVANCED********");
System.out.println("****************************************************");
//Get array size
System.out.println("How many words would you like to enter?");
arrayDimesion = sc.nextInt();
String[] wordArray = new String[arrayDimesion];
//Populate with user input
for (int i=0; i<arrayDimesion; i++) {
System.out.println("Please enter a word");
wordArray[i] = sc.nextLine();
}
//Print all entered Strings
System.out.println("This are the words you entered: ");
for(int i = 0; i < wordArray.length; i++) {
System.out.println(wordArray[i]);
}
//Print random string from array
int r = (int)(Math.random() * wordArray.length);
System.out.println("The random word is: " + wordArray[r]);
}
}
Change your
arrayDimesion = sc.nextInt();
to
arrayDimesion = Integer.parseInt(sc.nextLine());
Reason: sc.nextInt() doesn't consume the newline character that you give after taking arrayDimesion input. This later on gets consumed in the next sc.nextLine() call.
PS: It might throw NumberFormatException. So you can handle it like :
try {
arrayDimesion = Integer.parseInt(sc.nextLine());
} catch (NumberFormatException e) {
e.printStackTrace();
}
The below code is clean, easy to read and handles the edge cases.
import java.util.Scanner;
public class WordRandomizerAdvanced {
public static void main(String[] args) {
int numOfWords;
Scanner scanner = new Scanner(System.in);
System.out.println("****************************************************");
System.out.println("******** Welcome to Word Randomizer ADVANCED********");
System.out.println("****************************************************");
//Get array size
System.out.println("How many words would you like to enter?");
numOfWords = Integer.parseInt(scanner.nextLine());
String[] wordArray = new String[numOfWords];
//Populate with user input
System.out.println("Please enter the word(s)");
for (int i = 0; i < numOfWords; i++) {
wordArray[i] = scanner.nextLine();
}
//Print all entered Strings
System.out.println("These are the words you entered: ");
for (int i = 0; i < numOfWords; i++) {
System.out.println(wordArray[i]);
}
//Print random string from array
if (numOfWords == 0) {
System.out.println("You didn't enter a word");
} else {
int r = (int) (Math.random() * numOfWords);
System.out.println("The random word is: " + wordArray[r]);
}
}
}
This is my first question on this site, I'm running this on NetBeans 8.0.2 and trying to print out my user-defined array but it keeps returning null values. For example if you say there are 2 employees and enter both of their names, it will return [null, null]
How to fix this error? I'm a novice.
import java.util.Scanner;
import java.text.DecimalFormat;
import java.util.Arrays;
class Tips_Calculation2
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.print("How many employees for the week?: ");
int numberOfEmps = scan.nextInt();
// counter for the if statement that should return all employees from the array
int counter = numberOfEmps;
int[] nOEarray = new int[numberOfEmps];
System.out.println("\nEnter names of workers up to the entered amount (" + numberOfEmps + "):");
for(int i = 1; i <= numberOfEmps; i++)
{
String nameCycler = scan.next();
String[] namesArray = new String[i];
if(counter == i)
{
System.out.println(Arrays.toString(namesArray));
}
}
}
}
Disregard import java.text.DecimalFormat as I plan to use this import later on in my code. Thank you in advance to anyone who is kind/smart enough to respond.
First of all you never put your nameCycler to array. Second of all you create your namesArray every iteration which I think is wrong.
You're creating a brand new (full of null) array namesArray on every pass through the loop--and then never assigning anything to it. I think you're looking for something like this instead. Note that Java indexes from zero, not one.
String[] names = new String[numberOfEmps]
for(int i = 0; i < names.length; i++) {
names[i] = scanner.next();
}
System.out.println(Arrays.toString(names));
First of all, you should initialise the array outside of your loop. Secondly, you forgot to set the name to the array value(s).
Try this:
import java.util.Scanner;
import java.text.DecimalFormat;
import java.util.Arrays;
class Tips_Calculation2 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.print("How many employees for the week?: ");
int numberOfEmps = scan.nextInt();
int[] nOEarray = new int[numberOfEmps];
System.out.println("\nEnter names of workers up to the entered amount (" + numberOfEmps + "):");
String[] namesArray = new String[numberOfEmps];
for (int i = 0; i < numberOfEmps; i++) {
namesArray[i] = scan.next();
}
System.out.println(Arrays.toString(namesArray));
}
}
Replace
for(int i = 1; i <= numberOfEmps; i++)
{
String nameCycler = scan.next();
String[] namesArray = new String[i];
if(counter == i)
{
System.out.println(Arrays.toString(namesArray));
}
}
With
String[] namesArray = new String[numberOfEmps];
for(int i = 0; i < numberOfEmps; i++)
{
namesArray[i] = scan.next();
}
System.out.println(Arrays.toString(namesArray));
And see whether it works.
You never assign the name to the array and in every iteration you define the array new:
String[] namesArray = new String[numberOfEmps];
for(int i = 1; i <= numberOfEmps; i++)
{
String nameCycler = scan.next();
namesArray [i] = nameCycler ;
if(counter == i)
{
System.out.println(Arrays.toString(namesArray));
}
}
Added comments in the code to point out changes.
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.print("How many employees for the week?: ");
int numberOfEmps = scan.nextInt();
// removed 'nOEarray' and 'counter'
if (numberOfEmps > 0) {
System.out.println("\nEnter names of workers up to the entered amount (" + numberOfEmps + "):");
// initializing 'namesArray' outside for loop.
String[] namesArray = new String[numberOfEmps];
for(int i = 0; i < numberOfEmps; i++) { // initialized with 0 and updated condition with '<'
namesArray[i] = scan.next(); // assigning value to 'i'th position of namesArray
}
System.out.println(Arrays.toString(namesArray)); // Printing array outside for loop
}
}
"How to fix this error" not. This is not an error.
String[] namesArray = new String[i]; // step one, you declare an array of Strings
// which you don't initialize
if(counter == i)
{
System.out.println(Arrays.toString(namesArray));
//you print all the (non-initialized) elements of namesArray
//since you didn't initialize the elements, it takes the default value, which is null
}
fill the elements of the array with Strings before trying to print them.
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();
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);`