My program is to accept words (given as number of test cases) and print them out in reversed order. The problem is that whatever input of array size I may give, it only accepts just one word (and rest as blank). Can anyone help me figure out why? Here's the code:
import java.util.*;
public class terrible {
public static void main(String args[]){
Scanner input = new Scanner(System.in);
int test = input.nextInt();
while(test>0){
String str = input.nextLine();char c[] = str.toCharArray();
for(int i=0;i<str.length();i++){
System.out.print(c[str.length()-i-1]);
}
System.out.println();
test--;
}
}
}
Certain versions of Java don't let you take an int and then a string as input from the same Scanner. You can create another Scanner, like
Scanner input2 = new Scanner(System.in);
and then do
String str = input2.nextLine();
How do I input an array whose length may vary? The input is space delimited and ends when I press enter
public class ArrayInput {
public static void main(String args[]){
ArrayList<Integer> al = new ArrayList<Integer>();
Scanner sc = new Scanner(System.in);
while(){//what condition to use here?
al.add(sc.nextInt());
}
}
}
An example would be:
1 2 5 9 7 4 //press enter here to mark end of input
Since all your input is in a single line, you can read the entire line and then split it to integers :
String line = sc.nextLine();
String[] tokens = line.split(" ");
int[] numbers = new int[tokens.length];
for (int i=0; i<numbers.length;i++)
numbers[i] = Integer.parseInt(tokens[i]);
Read the entire line using sc.nextLine() and then split() using \\s+. This way, you don't have to worry about size of input (number of elements). Use Integer.parseInt() to parse Strings as integers.
I am trying to take string input in java using Scanner, but before that I am taking an integer input. Here is my code.
import java.util.*;
class prc
{
public static void main(String[] args)
{
Scanner input=new Scanner(System.in);
int n=input.nextInt();
for(int i=1;i<=n;i++)
{
String str=input.nextLine();
System.out.println(str);
}
}
}
The problem is that if I give a number n first, then the number of string it is taking as inputs is n-1.
e.g if the number 1 is entered first, then it is taking no string inputs and nothing is printed.
Why is this happening ?
Thanks in Advance!
nextLine() reads everything up to and including the next newline character.
However, nextInt() only reads the characters that make up the integer, and if the integer is the last (or only) text in the line, you'll be left with only the newline character.
Therefore, you'll get a blank line in the subsequent nextLine(). The solution is to call nextLine() once before the loop (and discard its result).
Information regarding the code is mentioned in the comments written next to each line.
public static void main(String[] args) {
int num1 = sc.nextInt(); //take int input
double num2 = sc.nextDouble(); //take double input
long num3 = sc.nextLong(); //take long input
float num4 = sc.nextFloat(); //take float input
sc.nextLine(); //next line will throw error if you don't use this line of code
String str = sc.nextLine(); //take String input
}
import java.util.*;
class prc
{
public static void main(String[] args)
{
String strs[];
Scanner input = new Scanner(System.in);
int n = input.nextInt();
input.nextLine();
strs = new String[n];
for(int i = 1; i < n; i++)
{
strs[i] = input.nextLine();
System.out.println(strs[i]);
}
}
}
This is my code:
package assignment.pkg1;
import java.util.Scanner;
public class Exercise3 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.print("Enter three integers: ");
byte t1 = scan.nextByte() , t2 = scan.nextByte(), t3 = scan.nextByte(); }
/* I'm getting this result for example:
Enter three integers: 10
20
30
I want to get this result: 10 20 30 */
How can i get the three inputs on the same line?
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
Use Regular Expressions, Pattern, and Matcher
String input = user_input.nextLine();
Pattern p = Pattern.compile("(\\d+)|([a-zA-Z]+)");
Matcher m = p.matcher(input);
List<String> nums = new LinkedList<String>();
while (m.find()) {
String num = m.group(1);
nums.add(num);
System.out.println(nums);
}
Take the input as a string. Use Regx and separate the string and get it into an array.
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int length = 3;
System.out.print("Enter three integers: ");
String s = scan.nextLine();
String[] array = s.split("\\s", -1);
for (int i = 0; i<array.length;i++){
System.out.println(array[i]);
}
}
You can safely enter all three numbers in one line, the way you want.
You need to read the entire line as a String.
Then split the line on spaces into an array of Strings.
Then parse the strings into bytes.
Scanner scanner = new Scanner(System.in);
System.out.print("Enter three integers: ");
String line = scanner.nextLine();
String[] numbers = line.split(" ");
byte t1 = Byte.valueOf(numbers[0]);
byte t2 = Byte.valueOf(numbers[1]);
byte t3 = Byte.valueOf(numbers[2]);
Keep in mind that you shouldn't press return until after you have entered the 3rd number.
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);`