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Java User Input array is only capturing 3 integers instead of five

This code is supposed to capture 5 user integers, print them out, then print them in reverse. It is capturing the first int only, and printing it 3 times, then printing the first integer again 5 more times without reversing. Test ends with "Process finished with exit code 0" which I think is says the program finished without errors -- which of course is not correct. I assume the issue is in how the user input array is stored. I have it assigning as userNum[i] with a limited array of 5, and int i =0 to begin array storage at userNum[0], so I'm not clear on why all the inputs are not captured up to userNum[4].
Thank you for any insight you can provide. I am very new to java and this is prework for my java class.
import java.util.Scanner;
public class ArrayReverse {
public static void main(String[] args) {
Scanner scnr = new Scanner(System.in); // scanner for input
final int NUM_VALS = 5; // number on int user able to enter
int[] userNum = new int[NUM_VALS]; // user integers storage
int j = 0;
int i = 0;
System.out.println("Enter integer values: ");
userNum[i] = scnr.nextInt(); // capture user input int
for (j = 0; j < NUM_VALS; j++) {
System.out.print("You entered: ");
System.out.println(userNum[i]);
++j;
}
System.out.print("\nNumbers in reverse: "); // statement to Print reversed array
for (j = NUM_VALS - 1; j >= 0; j--) {
System.out.print(userNum[i] + " ");
}
}
}

You need to work more about on for loops and study how to iterate values in for loop, the problem in your i,j variables.
Here I fix your code.
import java.util.Scanner;
public class ArrayReverse {
public static void main(String[] args) {
Scanner scnr = new Scanner(System.in); // scanner for input
final int NUM_VALS = 5; // number on int user able to enter
int[] userNum = new int[NUM_VALS]; // user integers storage
int j = 0;
int i = 0;
//for 5 inputs you need loop
for(;i<NUM_VALS;i++){
System.out.println("Enter integer values: ");
userNum[i] = scnr.nextInt(); // capture user input int
}
for (j = 0; j < NUM_VALS; j++) {
System.out.print("You entered: ");
System.out.println(userNum[j]);
//++j; //no need to increment as you already did in for loop
}
System.out.print("\nNumbers in reverse: "); // statement to Print reversed array
for (j = NUM_VALS - 1; j >= 0; j--) {
System.out.print(userNum[j] + " ");// userNum[0] = your last value which you reverse
}
}
}

Here is a solution using the collections framework:
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
public class ArrayReverse {
public static void main(String[] args) {
Scanner scnr = new Scanner(System.in); // scanner for input
final List<Integer> numbers = new ArrayList<>();
System.out.println("Enter any number of integers. (whitespace delimited. enter a non-integer to quit.): ");
while (scnr.hasNextBigInteger()) {
final int n = scnr.nextInt();
System.out.println("Parsed: " + n);
numbers.add(n);
}
System.out.println("Done reading user input.");
System.out.println("Your input: " + numbers);
Collections.reverse(numbers);
System.out.println("Your input reversed: " + numbers);
}
}

I have provided you with a solution. This is a clean way of doing it.
nextInt() reads the next integer that the user inputs. Notice that this will throw a InputMismatchExceptionif the user does not input a integer as value.
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
List<Integer> input = new ArrayList<Integer>();
//Simple loop that will read 5 user inputs
//and add them to the input list
for(int i = 0; i < 5; i++){
input.add(scanner.nextInt());
}
//print the 5 values
for(Integer val : input){
System.out.println(val);
}
//reverse the 5 values
Collections.reverse(input);
//print the 5 values again, but they are now reversed
for(Integer val : input){
System.out.println(val);
}
}

Why do I always get to enter a-1 strings in this string array?

Why do I always get to enter a-1 strings in this string array?
public class Source {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
// Declare the variable
int a;
// Read the variable from STDIN
a = in.nextInt();
String strs[]=new String[a];
for(int i=0;i<a;i++)
strs[i]=in.nextInt();
}
}

You can change condition in your loop, like this :
for (int i = 0; i < a - 1; i++) {
strs[i] = in.nextInt();
}

You are iterating correctly a number of times equal to a. Not a-1. So the question appears to be invalid:
public class Source {
public static void main(String[] args) {
try(Scanner in = new Scanner(System.in)) {
// Declare the variable
int a;
System.out.print("How many Strings would you like to enter? ");
// Read the variable from STDIN
a = in.nextInt();
String[] strs = new String[a]; // this will fail for certain values of `a`
for(int i=0; i<a; i++) {
System.out.format("Enter String number %d: ", i+1);
strs[i]= in.next();
}
System.out.println("Result: " + Arrays.toString(strs));
}
}
}
run:
How many Strings would you like to enter? 2
Enter String number 1: Apple
Enter String number 2: Pen
Result: [Apple, Pen]

Changing input variables in a java loop

I have an assignment, and I need to use a loop to allow a user to enter ten different numbers in a programme which then adds up the variables.
I have found various pieces of code and stitched them together to create this:
import javax.swing.*;
import java.util.Scanner;
public class exercise6
{
public static void main (String []args)
{
//Input
String totalNum, num1, num2, num3, num4, num5, num6, num7, num8, num9, num10;
Scanner in = new Scanner (System.in);
System.out.println("Please enter ten numbers:");
int[] inputs = new int[10];
for (int i = 0; i < inputs.length; ++i)
{
inputs[i] = in.next();
}
//Process
totalNum = num1 + num2 + num3 + num4 + num5 + num6 + num7 + num8 + num9 + num10;
//Output
JOptionPane.showMessageDialog(null, "Total = " + totalNum);
}
}
It's not great, but it's the best I have so far. Please help?

You don't need the variables num1 to num10. You can simply sum up in the loop itself. Like:
int sum = 0;
for (int i = 0; i < 10; i++) {
sum += = in.next(); // sum = sum + in.next();
}
Furthermore you assigned your variables as Strings, but you need int. In your case it would print something like 1111111111, if the input would always be a 1.
Take a look here how you would handle Integers properly.

You can achieve that in two ways, either inside the loop itself just add the number or if you need to keep track of them for later just add them to the array.
import javax.swing.*;
import java.util.Scanner;
public class exercise6
{
public static void main (String []args)
{
String total;
Scanner in = new Scanner (System.in);
int numOfInputValues = 10;
System.out.println("Please enter ten numbers:");
int[] inputs = new int[numOfInputValues];
for (int i = 0; i < numOfInputValues; ++i)
{
// Append to array only if you need to keep track of input
inputs[i] = in.next();
// Parses to integer
total += in.nextInt();
}
//Output
JOptionPane.showMessageDialog(null, "Total = " + totalNum);
}
}

First of all, your class should be in CamelCase. First letter is always in capital letter.
Second, you don't need an array to save those numbers.
Third you should make a global variable that you can change with ease. That is a good practice.
And you should always close stream objects like Scanner, because they leak memory.
import java.util.Scanner;
public class Exercise6 {
public static void main(String[] args) {
int numberQuantity = 10;
int totalNum = 0;
Scanner in = new Scanner(System.in);
System.out.println("Please enter ten numbers:");
for (int i = 0; i <= numberQuantity; i++) {
totalNum += in.nextInt();
}
in.close();
System.out.println(totalNum);
}
}

So the simplest answer I found is:
import javax.swing.*;
import java.util.Scanner;
public class exercise6
{
public static void main (String []args)
{
//Input
int totalNum, num1;
totalNum = 0;
for (int numbers = 1 /*declare*/; numbers <= 10/*initialise*/; numbers ++/*increment*/)
{
num1 = Integer.parseInt(JOptionPane.showInputDialog("Input any number:"));
totalNum = totalNum + num1;
}
//Output
JOptionPane.showMessageDialog(null, "Total = " + totalNum);

Try this way I only re-edit your code:
import javax.swing.*;
public class InputNums {
public static void main(String[] args) {
int total = 0;
for (int i = 0, n = 0; i < 10;) {
boolean flag = false;
try {
n = Integer.parseInt(JOptionPane
.showInputDialog("Input any number:"));
} catch (NumberFormatException nfe) {
flag = true;
}
if (flag) {
flag = false;
JOptionPane.showMessageDialog(null,
"Invalid no Entered\nEnter Again...");
continue;
}
total += n;
i++;
}
JOptionPane.showMessageDialog(null, "Total = " + total);
}
}

NULL Array - how to link it in while loop

Basically I have to prompt a user to enter 10 string values, and then in another loop print them in ascending order, then in a final loop, print them in descending order. My array is bringing back null, obviously because I am not prompting users to enter actual information into the array object. I am really stuck on this. I know I need to somehow reference the "userStrings[]" array in my first while loop. I keep researching and keep getting integer loops questions and For loops. This has to be a while loop. I just can no figure out how to get the userStrings[] to actually fill up when the user enters the values. How do I get it linked in the loop?
public class HomeWork10
{
public static void main(String[] args)
{
String[] userStrings = new String[10];
int count = 0;
int count2 = 0;
while (count < 10)
{
System.out.println("Please enter a string value ");
Scanner input = new Scanner(System.in);
String userInput = input.next();
count++;
}
while (count2 < 1)
{
System.out.println(Arrays.asList(userStrings));
count2++;
}
}
}

You are not putting the values in the String[]
Do it like this:
while (count < 10) {
System.out.println("Please enter a string value ");
Scanner input = new Scanner(System.in);
String userInput = input.next();
userStrings[count] = userInput;
count++;
}
Also, declare Scanner input = new Scanner(System.in) outside your while() {...}

See below code snippet may solve your problem.
package com.suresh;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;
public class HomeWork10 {
public static void main(String[] args) {
String[] userStrings = new String[10];
int count = 0;
System.out.println("\t Reading Array Elements ");
while (count < 10) {
System.out.print("\t Please enter a string value : ");
Scanner input = new Scanner(System.in);
userStrings[count] = input.next();
count++;
}
System.out.println("\t PRINTING ORIGINAL ARRAY OF ELEMENTS ");
count = 0;
while (count < userStrings.length) {
System.out.println("\t " + userStrings[count]);
count++;
}
Collections.sort(Arrays.asList(userStrings), new StringAscComparator());
System.out.println("\t ASCENDING ORDER ");
count = 0;
while (count < userStrings.length) {
System.out.println("\t " + userStrings[count]);
count++;
}
System.out.println("\t DESCENDING ORDER ");
Collections.sort(Arrays.asList(userStrings), new StringDescComparator());
count = 0;
while (count < userStrings.length) {
System.out.println("\t " + userStrings[count]);
count++;
}
}
static class StringAscComparator implements Comparator<String> {
#Override
public int compare(String o1, String o2) {
return o1.compareTo(o2);
}
}
static class StringDescComparator implements Comparator<String> {
#Override
public int compare(String o1, String o2) {
return o2.compareTo(o1);
}
}
}

You created the array with 'String[] userStrings = new String[10];' and inside your while loop to access it you need to do something like this 'userStrings[0] = input.next()' This says the first item in the array userStrings will be set to input.next(). I'm not great at java so I'm not sure what input.next() will do though.

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.