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How to write Java statement to display integers between 2 numbers?

I am new to java coding. I have written the code below to the problem: How can I write a statement that can be used in a Java program to read two integers and display the number of integers that lie between them, including the integers themselves?
I couldn't run it in Eclipse. When I try to run it through Eclipse, it tells me "The selection cannot be launched, and there are no recent launches. Anyway, can someone please tell me if this code correct? Are there any errors in it?
import java.util.Scanner;
public class Assignment4 {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.print("Enter the first integer:10");
int first = s.nextInt();
System.out.print("Enter the second integer:20");
int second = s.nextInt();
System.out.println("How many integers are between "+first+" and "+second+"???");
}
}

Please put some more effort on your query, for sure you can come up with your answers by yourself and you will learn faster. For now You can refer to below answer.
package com.barnwal.jeetendra.learn;
import java.util.Scanner;
public class Assignment4 {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.print("Enter the first integer:");
int first = s.nextInt();
System.out.print("Enter the second integer:");
int second = s.nextInt();
System.out.println("How many integers are between " + first + " and "
+ second + "???");
// To print number of integer between entered number
if (second > first) {
System.out.println("Answer : " + (second - first - 1));
// To print the numbers
for (int i = first + 1; i < second; i++)
System.out.print(i + " ");
} else {
// To print number of integer between entered number
System.out.println("Answer : " + (first - second - 1));
// To print the numbers
for (int i = second + 1; i < first; i++)
System.out.print(i + " ");
}
}
}

To avoid the unnecessary if-else statement to look which value is bigger, you can also use the functionality of the class java.lang.Math like this
Scanner s = new Scanner(System.in);
System.out.print("Enter the first integer:");
int first = s.nextInt();
System.out.print("Enter the second integer:");
int second = s.nextInt();
int small = Math.min(first, second) ;
int big = Math.max(first, second);
System.out.println("How many integers are between " + small + " and " + big + "???");
System.out.println("Answer : " + (big - small + 1));
// To print the numbers
for (int i = small; i <= big; i++)
System.out.print(i + " ");

You can use looping like this:
if (first > second){
big = first;
small = second;
}
else if (second > first){
big = second;
small = first;
}
for (int i = small; i <= big; i++)
System.out.print(i + " ");

first of all, when you use resources (System.in) you should close them. You can do it with try-finally or you can use try-with-resources.
Here is your code:
import java.util.Scanner;
public class Assignment4 {
public static void main(String[] args) {
try (Scanner s = new Scanner(System.in)){
System.out.print("Enter the first integer:10");
int first = s.nextInt();
System.out.print("Enter the second integer:20");
int second = s.nextInt();
System.out.println("How many integers are between "+first+" and "+second+"???");
if (first != second)
System.out.println("Answer: " + Math.abs(first-second - 1));
else
System.out.println("Answer: 0");
}
}
}

How about this:
int diff = second - first - 1;
let secont = 25 and first = 23 so the output will be:
25-23-1 = 1;
which is 24

How do I output a TABLE with names and scores with only using Arrays and Methods?

I have been trying to find the answer to this question but to no avail!
Basically I have to write a program where 'x' number of players can enter a guessing game and input their guesses and then get a score.
However, right after they input their guesses, i have to output it in a table form like this "NAME GUESS SCORE"
I do not know how i can do this with a for loop since a for loop println can only print values from playersArray. How can I print another array like guessesArray to the side of it?
I can only use Arrays and Methods to do this.
Below I will show u what i have right now:
import java.util.Scanner;
import java.util.Random;
import java.lang.Math;
public class game
{
static int[] guessesArray;
static int guess;
static String [] playersArray;
static int[] currscoresArray;
static int [] addscoresArray;
static int [] finalscoresArray;
public static void main(String [] args){
System.out.print("Number of players? ");
Scanner kb = new Scanner(System.in);
int numplayers = kb.nextInt();
//Initialize
playersArray = new String[numplayers];
guessesArray = new int [numplayers];
currscoresArray = new int [numplayers];
addscoresArray = new int [numplayers];
finalscoresArray = new int [numplayers];
populateArray(playersArray);
displayMenu();
}
public static void populateArray( String[] x){
Scanner kb = new Scanner(System.in);
for (int i = 0; i<x.length ; i++){
System.out.print("Enter Player "+(i+1)+": ");
x[i]=kb.nextLine();
}
}
public static void displayMenu(){
int choice=0;
Scanner kb = new Scanner(System.in);
String[] args = {};
while(true){
System.out.println("Menu ");
System.out.println("1. Make Guess");
System.out.println("2. List Winner");
System.out.println("0. Exit");
System.out.print("Enter choice: ");
choice = kb.nextInt();
if (choice==0){
System.out.print("Do you want to play a new game? Y/N: ");
String ans = kb.next();
if (ans.equals ("Y") || ans.equals ("y")){
main(args);
}
break;
}
switch (choice){
case 1: makeGuess(); break;
case 2: listWinner(); break;
default: System.out.println("Invalid choice");
}
}
System.out.println("End of program");System.exit(0);
}
public static void makeGuess(){
Scanner kb = new Scanner(System.in);
Random rand = new Random();
int secret = rand.nextInt(10)+1;
for (int i=0; i < guessesArray.length; i++){
System.out.print("Enter your guess "+playersArray[i]+": ");
guessesArray[i]=kb.nextInt();
}
int diff = (int)(Math.abs(guess - secret));
int score=0;
if (diff == 0){
score=score+10;
}else if(diff<=1){
score=score+5;
}else if(diff<=2){
score=score+2;
}
for (int i=0; i< currscoresArray.length; i++){
currscoresArray[i]=score;
}
System.out.println();
System.out.println("Generated number is "+secret);
System.out.println("Current Score Listing");
System.out.println(" Name Guess Score Added Final Score");
System.out.println("1. "+playersArray[0]+" \t "+guessesArray[0]+" \t"+currscoresArray[0]+"");
System.out.println("1. "+playersArray[1]+" \t "+guessesArray[1]+" \t"+currscoresArray[1]+"");
}
public static void listWinner(){
}
}

just reuse a int x variable when printing from each array?
for( int x = 0; x < playersArray.length; x++ ) {
System.out.println( playersArray[ x ] + ” ” + guessArray[ x ] + " " + finalScoresArray[ x ] );
}
you already give an example in your code where you print the 3 values with a single print method. you used a for loop for indexing an element in an array. So combing the 2 techniques shouldn't be too difficult to grasp.

Instead of using an enhanced for loop (e.g. for (String player : playersArray) {}, you can use an indexed one:
for (int i = 0; i < playersArray.length; i++) {
String name = playerArray[i];
double score = scoresArray[i];
}
That being said, you should really make a Player class, that holds all information of a single player, and then have just one array, of that type. That's much nicer, not only because you can use enhanced fors, but because you don't need to make sure the arrays are always synced, and your code becomes way easier to understand.

Store/ Display Data Inputs from Arrays

I'm having problems on how and where to put arrays.
I figured out how and where to put a loop so it will keep on gathering multiple user data that will be stored inside the arrays but I don't know where to put arrays. There will be an array for product numbers, an array for product name, and an array for price.
import java.io.*;
public class DataInsideArrays
{
public static DataInputStream a = new DataInputStream(System.in)
public static void main(String args[])throws Exception
{
int y = 0;
for(int x=1;x<=100;x++)
{
System.out.println("1 - Maintenance");
System.out.println("2 - Transaction");
System.out.println("");
System.out.print("Enter code: ");
int code =
Integer.parseInt(a.readLine());
System.out.println("");
if(code==l)
{
System.out.print("") ;
System.out.print("Product number: ");
System.out.print("Product name: ");
String prodname = a.readLine();
System.out.print("Price: ");
int price = Integer.parseInt(a.readLine());
System.out.println("");
}
else if(code==2)
{
System.out.println("Display List of Products-Prices")
System.out.print("Enter product number:
") ;
int prodnum
Integer.parseInt(a.readLine());
System.out.println("")
}
if(code==3)
{
System.out.println("Invalid");
System.out.println("Restart");
System.out.println("");
}}}}

First of all, where do you get this l (lowercase L) value in your for loop? Shouldn't this be 1 (number one)? Furthermore, it would be even better if it is 0 (zero) so you can use it as an index for your array.
Second thing, what's the point of int y = 0'? You are not using y anywhere in your program.
int y = 0;
for(int x = l; x <= 100; x++)
Change it to:
for(int x = 0; x < 100; x++)
Since you want to have 3 separate arrays, you should have 3 separate indexes to keep track of them.
Now let's see how to initialize an array to store the data. You should declare the size as a variable at the top of your class (or locally in your main()) to make it easier to change it later across your program. You can do the same with your array. Declare it inside your class or locally inside the main(). I will show you how to declare both outside of the class, but you should try it the other way too for practice.
Now remember, when using arrays you have to know the size of the array in advance as soon as you create it and you cannot change that size after. This means only that many elements can fit inside the array. If you want variable size structures, check out some of the answers with ArrayLists.
public class DataInsideArrays
{
public static DataInputStream a = new DataInputStream(System.in)
public static int size = 100; // now you only change this number and everything works
public static int[] productNumbers = new int[size];
public static String[] productNames = new String[size];
public static int[] productPrices = new int[size];
public static void main(String args[]) throws Exception
{
int prodnumIndex = 0; // index for tracking product numbers
int prodnameIndex = 0; // index for tracking product names
int prodpriceIndex = 0; // index for tracking product prices
for(int x = 0; x < size; x++)
{
// ... your code...
// ...
int prodNum = Integer.parseInt(a.readLine());
// check if we didn't reach our maximum size
if(prodnumIndex < productNumbers.length) {
productNumbers [prodnumIndex] = prodnum;
prodnumIndex++; // increment
} else {
System.out.println("Cannot add product number. Reached maximum amount.");
}
// ...
String prodName = a.readLine();
// check if we didn't reach our maximum size
if(prodnameIndex < productNames.length) {
productNames [prodnameIndex] = prodName ;
prodnameIndex++; // increment
} else {
System.out.println("Cannot add product name. Reached maximum amount.");
}
// ...
int prodPrice = Integer.parseInt(a.readLine());
// check if we didn't reach our maximum size
if(prodpriceIndex < productPrices.length) {
productPrices [prodpriceIndex] = prodPrice ;
prodpriceIndex++; // increment
} else {
System.out.println("Cannot add product number. Reached maximum amount.");
}
// ...
}
Another way you can achieve this is to create an object called Product that will contain the properties you need and then have an array of that object.
class Product {
int num;
String name;
int price;
Product(int num, String name, int price) {
this.num = num;
this.name = name;
this.price = price;
}
}
// ...
// declare your array of `Product` objects...
Product[] products = new Product[size];
// ...
// then you can do something like
System.out.println("Enter product number:");
int prodNum = Integer.parseInt(a.readLine());
System.out.println("Enter product name:");
String prodName = a.readLine();
System.out.println("Enter product price:");
int prodPrice = Integer.parseInt(a.readLine());
products[INDEX] = new Product(prodNum, prodName, prodPrice);
// ...
Also, consider using a double of a float for the product price since it is more realistic representation of actual products.

Do you have to use an array and "if" statements?
Common practice is to use a List as switch statement:
int[] productArray = new int[100];
List<Integer> productList = new ArrayList<Integer>();
for(int x=1;x<=100;x++) {
switch (code){
case 1:
productArray[x-1] = Integer.parseInt(a.readLine());
productList.add(new Integer(a.readLine()) );
break;
default:
System.out.println("Invalid")
break;
}
}

You should use a List instead of an array, because you don't know a priori the length for them.
A List allows you to dinamically add an element as soon as you got it, so you should "put the array" under the user input.
List<String> names = new ArrayList<String>(); //<-- do the same for price(Integer) and product number (Integer)
public static void main(String args[]) throws Exception) {
//...
if(code==1) //<-- This was a l, check again your code.
{
System.out.print("") ;
System.out.print("Product number: ");
System.out.print("Product name: ");
String prodname = a.readLine();
names.add(prodname); //<-- add value to ArrayList
System.out.print("Price: ");
int price = Integer.parselnt(a.readLine());
System.out.println("");
}
//...
}
To print the array content you just need to iterate over the ArrayList:
for(String prodname: names)
System.out.println(prodname); //<-- This will print all your product names

public class DataInsideArrays {
public static DataInputStream a = new DataInputStream(System.in);
List<String> productname=new ArrayList<String>();
public static void main(String args[]) throws Exception {
// rest of your code...
if(code == 1) {
System.out.print("") ;
System.out.print("Product number: ");
System.out.print("Product name: ");
String prodname = a.readLine();
System.out.print("Price: ");
int price = Integer.parseInt(a.readLine());
System.out.println("");
////////////////////////to store data place arraylist here/////////////////////////////
productname.add(prod);
///////////////////// //same way use arr to store price and product no
} else if(code == 2) {
System.out.println("Display List of Products-Prices") ;
System.out.print("Enter product number:") ;
int prodnum=Integer.parseInt(a.readLine());
System.out.println("");
}
if(code == 3) {
System.out.println("Invalid");
System.out.println("Restart");
System.out.println("");
}
}
}

Here's the correct codes for the output I want. Maybe is there any other way I can get the same output of this with different coding?
import java.io.*;
import java.util.ArrayList;
public class DataArrays
{
public static DataInputStream a = new DataInputStream(System.in);
public static void main(String args[])throws Exception
{
ArrayList<Integer> prodNum = new ArrayList<Integer>(100);
ArrayList<String> prodName = new ArrayList<String>(100);
ArrayList<Integer> prodPrice = new ArrayList<Integer>(100);
ArrayList<Integer> prodPay = new ArrayList<Integer>(100);
for(int x=1;x<=100;x++)
{
System.out.println("1 - Maintenance");
System.out.println("2 - Transaction");
System.out.println("");
System.out.print("Enter code: ");
int code = Integer.parseInt(a.readLine());
System.out.println("");
int y = 1;
if(code==1)
{
System.out.print("") ;
System.out.println("Product number: "+ x);
prodNum.add(x); //this brings 1st input to array element #0 which is not needed
prodNum.add(x);
System.out.print("Product name: ");
String prodname = a.readLine();
prodName.add(prodname); //this brings 1st input to array element #0 which is not needed
prodName.add(prodname);
System.out.print("Price: ");
int prodprice = Integer.parseInt(a.readLine());
prodPrice.add(prodprice); //this brings 1st input to array element #0 which is not needed
prodPrice.add(prodprice);
System.out.print("Payment: ");
int prodpay = Integer.parseInt(a.readLine());
prodPay.add(prodpay); //this brings 1st input to array element #0 which is not needed
prodPay.add(prodpay);
System.out.println("");
System.out.println("Start New Transaction:");
System.out.println("");
}
else if(code==2)
{
System.out.println("Display List of Products-Prices");
System.out.print("Enter product number: ");
int i = Integer.parseInt(a.readLine());
i = prodNum.get(i); //this gets the data stored in the arraylist. Assuming it starts with 1 and above
prodNum.set(1, i);
System.out.println("");
System.out.println("Product name: "+ prodName.get(i));
System.out.println("Product price: "+ prodPrice.get(i));
System.out.println("Product payment: "+ prodPay.get(i));
System.out.println("");
System.out.println("Start New Transaction:");
}
else if(code>=3)
{
System.out.println("Invalid");
System.out.println("Restart");
System.out.println("");
}
else if(code==0)
{
System.out.println("Program will end");
break;
}}}}
Thank for helping me guys. Really appreciated it.

Basic Arrays in a Java Program

I am a beginner in Java and am working on a basic program that includes arrays and loops. The program must:
- ask the user to enter the name of a 'salesman' 5 times. These 5 names will be stored into a String array.
- another DOUBLE array is used to store the amount of sales each person has made.
- the data will be printed in the end.
Here's what I have so far:
public static void main (String[] args)
{
String[] names = new String[5];
System.out.println ("What is the name of the person?")
String name = scan.next();
double[] sales = new double[5];
sales[0] = 15000.00;
sales[1] = 10000.00;
sales[2] = 4500.00;
sales[3] = 2500.00;
sales[4] = 3500.00;
System.out.println(name1 + "sold " + sales[0]);
System.out.println(name2 + "sold " + sales[1]);
System.out.println(name3 + "sold " + sales[2]);
System.out.println(name4 + "sold " + sales[3]);
System.out.println(name5 + "sold " + sales[4]);
}
}
I know the first part is incorrect... as well as most of the output.
My instructor is not very interested in explaining much to our class. She is usually too busy working with a different part of the class. I basically know nothing about arrays.
I will certainly learn something if one of you is kind enough to tell me what I need to enter and where?

You need to use for loops to avoid having to repeat the lines of code for each instance. You want something more like this:
public static void main (String[] args)
{
String[] names = new String[5];
double[] sales = new double[5];
Scanner scan = new Scanner(System.in);
for (int i=0; i<5; i++) {
System.out.println ("What is the name of the person?");
name[i] = scan.next();
System.out.println ("How much did they sell?");
sales[i] = scan.nextDouble();
}
for (int i=0; i<5; i++) {
System.out.println (name[i] + " sold " + sales[i]);
}
}
look here http://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html for more on how to use the for loop. The loops that I wrote will execute the code inside when i=0, 1, 2, 3 and 4. i=0 tells the loop where to begin. i<5 tells the loop to execute the code inside as long as i is less than 5. And i++ is shorthand for i=i+1 and tells the loop what to do to i at the end (increase i by 1 and test the end condition again).
ETA: http://www.homeandlearn.co.uk/java/user_input.html shows how to use the Scanner class to get input.

It will be easier when you use collections.
Use this for simple implementation and better understanding for collections.
Scanner scanner = new Scanner(System.in);
List<String> list = new ArrayList<String>();
for (int i = 0; i < 5; i++) {
list.add(scanner.nextLine());
}
For printing use this.
for(String result : list){
System.out.println(result);
}

Simply use Scanner inside a loop.
String[] names = new String[5];
double[] sales = new double[5];
Scanner scanner = new Scanner(System.in);
for(int i = 0; i < names.length; i++){
System.out.print ("Please input name of sale " + (i+1) + ": ");
names[i] = scanner.nextLine();
System.out.print ("Please input sales of sale " + (i+1) + ": ");
sales[i] = scanner.nextDouble();
}
// following lines is for testing
for(int i=0; i < names.length; i++){
System.out.println(names[i]+" " + sales[i]);
}
Since Java is a Object oriented, so I recommend you to create a class named Salesman containing name and sale attributes.
// Salesman class
class Salesman{
private String name;
private double sales;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getSales() {
return sales;
}
public void setSales(double sales) {
this.sales = sales;
}
}
And once again the main method.
public static void main (String[] args)
{
List<Salesman> salesmanList = new ArrayList<Salesman>(5);
Scanner scanner = new Scanner(System.in);
for(int i = 0; i < 5; i++){
Salesman salesman = new Salesman();
System.out.print ("Please input name of sale " + (i+1) + ": ");
salesman.setName(scanner.nextLine());
System.out.print ("Please input sales of sale " + (i+1) + ": ");
salesman.setSales(scanner.nextDouble());
salesmanList.add(salesman);
}
// following lines is for testing
for(Salesman salesman : salesmanList){
System.out.println(salesman.getName()+" " + salesman.getSales());
}
}

Try this:
public void getInput(){
Scanner scanner = new Scanner(System.in);
System.out.println("Enter the total no of i/p :")
int count = scanner.nextInt();
List<String> collectionOfInput = new ArrayList<String>();
for (int i = 0; i < count; i++) {
collectionOfInput.add(scanner.nextLine());
}
}
public void printOutput(){
for(String outputValue : collectionOfInput){
System.out.println(result);
}

Finish input to array before printing all

I am trying to do input to an array until it is full and after that print the entire array. But I cannot get the loop to run until the array is full and after that print all.
Here is my code:
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
String[] course = new String [2]; //creating array
int [] grade = new int [2];
System.out.println("Input coursename and grade: ");
for (int i = 0; i < course.length; i++){
course[i] = input.next();
grade [i] = input.nextInt();
if (i == course.length)
break;
//System.out.println("\nHow do you want to order course and grade?");
//System.out.print(" 1 - Ascending?\n"
// + " 2 - Decending?\n");
//System.out.println("Name and grade is " + course[i] + " " + grade[i]);
System.out.println(Arrays.toString(course)+(grade));
}
}
}
How can get the loop to run and then jump to the print statement?

the variable i in the loop can never be equal to course.length because the loop runs only until i < course.length. So the if block is redundant anyway.
The printing statement should be AFTER the for block, otherwise you'd be printing the array in each iteration.
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
String[] course = new String [2]; //creating array
int [] grade = new int [2];
System.out.println("Input coursename and grade: ");
for (int i = 0; i < course.length; i++) {
course[i] = input.next();
grade [i] = input.nextInt();
}
System.out.println(Arrays.toString(course)+(grade));
}

There should be a } after grade [i] = input.nextInt();.
And the following if is not necessary at all.

It seems the loop would do the job if it was closed after the two assignment statements. The check afterwards isn't useful and could be removed.
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
String[] course = new String[2]; // creating array
int[] grade = new int[2];
System.out.println("Input coursename and grade: ");
for (int i = 0; i < course.length; i++) {
course[i] = input.next();
grade[i] = input.nextInt();
}
System.out.println(Arrays.toString(course) + (grade));
}

if (i == course.length) is unnecesery because when i == length then for loop finish working and for-loop-body doesn't call so remove this line and put instead of it close loop "}"
Next is printing your array. Change the last line to:
System.out.println(Arrays.toString(course) + Arrays.toString((grade)));