I am trying to create an array that uses a user input string to form the base for the array. It's supposed to be an encryption program that takes the string the user enters and puts it in an array at the index 0, all the way down the column. For example, if I typed in car, the array would look like array[0][0] c, [1][0] a, [2][0] r. After the encryption, whatever car turns into would go into the second row, but for the life of me I can't even figure out how to create the first array.
So far my file looks like this:
public class Csci1301_hw3
{ //Start of class
public static void main(String[] args)
{ //Start of Main Method
String userinput;
Scanner scan = new Scanner(System.in);
System.out.println("Please enter a sentence you would like to encrypt.");
userinput = scan.nextLine();
char current;
int arraylength = userinput.length();
char[][] outputarray = new char [arraylength][];
for (int index=0; index < arraylength; index++);
{
if (current.charAt(0) < userinput.charAt(0))
current = userinput.charAt(0);
outputarray[0][0] = current;
current++;
}
String userinput;
Scanner scan = new Scanner(System.in);
System.out.println("Please enter a sentence you would like to encrypt.");
userinput = scan.nextLine();
char current;
int arraylength = userinput.length();
char[][] outputarray = new char [arraylength][];
for (int index=0; index < arraylength; index++);
{
if (current.charAt(0) < userinput.charAt(0))
current = userinput.charAt(0);
outputarray[0][0] = current;
current++;
}
This is my first coding class so I am very new to this, but even after rewatching lectures, reading my textbook, or even going over my professor's examples, I am unable to figure this out. The closest I got was it would just print out null for the entire array no matter what I typed.
I think there are a couple of things you might want to check, first your current variable,you should assign a value to it before using it in an if statement. second, I think you might want to consider using the index variable inside the if statement like:
userinput.charAt(index);
and in other places too. Because you want to go over all the chars in a string. the last thing I wasn't sure about is why incrementing the current variable?
update:
String userInput;
Scanner stdin = new Scanner(System.in);
System.out.println("Please enter a sentence you would like to encrypt.");
userInput = stdin.nextLine();
int arraylength = userInput.length();
char[][] outPutArray = new char [arraylength][2];
for (int i = 0; i < arraylength; i++)
{
outPutArray[i][1] = userInput.charAt(i);
}
for (int i = 0; i< outPutArray.length; i++)
System.out.print(outPutArray[i][1]);
I am creating a cash register where I have to use a scanner and can only have 5 input amounts. It has to also include hst and that is by only having a "h" after or before an amount. My question is how would the program recognize that I have put an "h" after or before an amount? This seems to be done only using a string variable, so how would I accomplish that? I have to store the inputs in an array, and so I got that to work.
My Code:
// Import scanner class
import java.util.Scanner;
// Create class and method
class Main {
public static void main(String[] args) {
// Declare the scanner object and create scanner variables
Scanner inp = new Scanner(System.in);
System.out.println("Press any key to start");
String key = inp.nextLine();
System.out.println("\nEnter the amount of each item");
System.out.println("Upto 5 inputs are allowed!\n");
// Define an array double variable, set the limit to 5 inputs
double[] numbers = new double[5];
// Create a for loop to input any numbers 5 times
for (int i = 0; i < numbers.length; i++){
// Add a scanner input to let the user type out the values
numbers[i] = inp.nextDouble();
}
}
}
below code asks the user input for 5 times , and only valid values will be in the Array , Vald values are the values with 'h' at start or end and should only occur once. i.e. at 'h' at both end and start or more than once is invalid.
public static void main(String[] args) throws ParseException {
int counter = 1;
Double[] result = new Double[5];
int index = 0;
while(counter <= 5) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter an Amount ");
String value = scanner.nextLine();
int indexOfH = value.indexOf("h");
int lastIndexOfH = value.lastIndexOf("h");
boolean containsHatstartsOrEnd = indexOfH == 0 || indexOfH == (value.length()-1);
if(containsHatstartsOrEnd && indexOfH==lastIndexOfH){ //Validate h at begins or end and should contains only once
result[index] = Double.parseDouble(value.replace("h", ""));
index++;
}
counter++;
}
System.out.println("Printing Valid values");
for(int i=0; i< result.length; i++) {
if(result[i]!=null) {
System.out.println(result[i]);
}
}
}
input & result
Enter an Amount 13.45h
Enter an Amount 55h.65
Enter an Amount 32h.33h
Enter an Amount h100.23
Enter an Amount h20
Printing Valid values
13.45
100.23
20.0
I had a assignment for school but I'm stuck and could use some tips.
The assignment is that I need to make a array and let the user put data in the array by using a scanner and a loop. If the user puts a empty string in the scanner the scanner should stop and should print out the array. Also the array cannot be longer then 25 length.
public class invoerOpslaan {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
String[] arrayList = new String[25];
String input;
int i = 0;
for (input = scanner.nextLine(); !input.isEmpty(); input = scanner.nextLine()) {
arrayList[i] = input;
i++;
}
System.out.println(arrayList[]);
}
I have my array set to be 25 length but how can I make it so that a user puts in 15 strings in the array that the array will be 15 instead of 25. And if the user puts the 25th string in the array it will automatically stop the scanner and print out the array.
If you are not allowed to use a List then loop through every element that contains a value in the array and create a new array (with the size of i) using all of those elements.
Scanner scanner = new Scanner(System.in);
String[] arrayList = new String[25];
String input;
int i = 0;
for (input = scanner.nextLine(); (!input.isEmpty() && i < 25); input = scanner.nextLine()) {
arrayList[i] = input;
i++;
}
String[] newArrayList = new String[i];
int index = 0;
for (String element : arrayList) {
if (element == null)
continue;
newArrayList[index] = element;
index++;
}
You can use an ArrayList to give a dynamic size array to your code.
Scanner scanner = new Scanner(System.in);
ArrayList<String> arrayList = new ArrayList<>();
String input;
int i = 0;
for (input = scanner.nextLine(); !input.isEmpty(); input = scanner.nextLine()) {
arrayList.add(input);
i++;
}
System.out.println(arrayList);
And System.out.println will give you an output like this:
[Hello, World!]
If you cannot use a List you can use Arrays.copyOf() and i to copy as many elements as the user inputted to a new Array. Also you don't actually check to make sure i is less than 25. Make sure you check in your loop:
for (input = scanner.nextLine(); !input.isEmpty() && i < 25; input = scanner.nextLine()) {
arrayList[i] = input;
i++;
}
String[] temp = Arrays.copyOf(arrayList, i);
System.out.println(Arrays.toString(temp));
I keep getting the error "cannot find symbol 'arr' " How do I accept both the array as a user input (being a float not a double) and 3 float variables as elements in the array?
import java.util.Scanner;
public class runtime_array
{
public static void main(String[] args){
System.out.println("Program creates array size at run-time");
System.out.println("Program rounds sum and average of numbers to two decimal places");
System.out.println("Note: numbers *must* be float data type");
System.out.println(); //blank line
// taking String array input from user
Scanner input = new Scanner(System.in);
System.out.println("Please enter length of String array");
int length = input.nextInt();
arr[i] = input.nextInt();
// create an array to save user input
float[] input = new float[length];
float[] input = new float[arr];
// loop over array to save user input
System.out.println("Please enter array elements");
for (int i = 0; i < length; i++) {
}
float sum = 0;
System.out.println("The array input from user is : ");
for(int i = 0; i < arr.length; i++){
System.out.println(String.format("%.2f", Float.valueOf(arr[i])));
sum += Float.valueOf(arr[i]);
}
System.out.println("The sum is: " + String.format("%.2f",sum));
System.out.println("The average is: " + String.format("%.2f",(sum/length)));
}
}
You've got a couple issues here
First, you cannot declare float[] input because you've already given Scanner to the reference for input. You need to name your float[] something different. Let's go with userInput.
Scanner input = new Scanner(System.in);
System.out.println("Please enter length of String array");
int length = input.nextInt();
float[] userInput = new float[length];
Next, you are trying to do things with arr before you have declared it. However, I don't even think you need a reference to arr. You should remove this line.
arr[i] = input.nextInt();
Furthermore, you need to prompt your user during each loop iteration, as well as append the Scanner input to float[] userInput.
for (int i = 0; i < length; i++) {
System.out.println("Please enter array elements");
userInput[i] = input.nextInt();
}
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);`