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Stuck with detecting next line from console

I am banging my head to the wall but just can't figure out what is going wrong. Simple program but not working. I need to get 3 inputs(integers) from user. End the program on either array full or when user presses enter. Here is what i am trying without any luck. It works fine all the situtations EXCEPT it cant detect nextline.
Scanner sc = new Scanner(System.in);
int[] intArray = new int[3];
int counter = 0;
System.out.println("Start!!");
while (true) {
System.out.println("Enter int");
if (sc.hasNextInt() && counter <= 2) {
intArray[counter] = sc.nextInt();
counter++;
} else {
if (counter >= 3) {
System.out.println("Array is full");
System.out.println("Array ELemnets : " + Arrays.toString(intArray));
break;
}
if (sc.next().isEmpty() || sc.next().equals("\n")){
System.out.println("Its empty");
break;
} else {
System.out.println("wrong input.");
}
}
}
sc.close();
Please help me . Why is it not detecting next line. I have googled already and tried lot of solutions provided but none worked for me. Any HELP!!!
Thanks
Edited code :
Scanner sc = new Scanner(System.in);
int[] intArray = new int[3];
int counter = 0;
System.out.println("Start!!");
while (true) {
System.out.println("Enter int");
if (sc.hasNextInt() && counter <= 2) {
intArray[counter] = sc.nextInt();
counter++;
} else {
if (counter >= 3) {
System.out.println("Array is full");
System.out.println("Array ELemnets : " + Arrays.toString(intArray));
break;
}
String next = sc.next();
if (next.isEmpty() || next.equals("\n"))
{
System.out.println("Its empty");
break;
} else {
System.out.println("wrong input.");
}
}
}
sc.close();
}

int[] intArray = new int[3];
int counter = 0;
boolean enterPressed = false; // added boolean to test if they entered a blank line
try (
Scanner sc = new Scanner(System.in); // declaring in a try-with-resources, so it automatically closes.
) {
System.out.println("Start!!");
System.out.println("Enter int"); // Have to print this the first time
while (counter < 3 && !enterPressed) {
if (counter > 0) { System.out.println("Enter int"); }
String next = sc.nextLine(); // just grab a line (the user pressed enter)
if (next.isEmpty()) {
enterPressed = true;
} else {
try {
intArray[counter] = Integer.parseInt(next);
counter++;
} catch (NumberFormatException ex) {
System.out.println("wrong input.");
}
}
}
}

Your code is sticking because it's waiting on the conditional check for sc.hasNextInt(). The solution I propose below, manually parses the user-input string to see if it's an int, rather than using the Scanner's functionality to check if it's an int or not.
I left some comments in the code to hopefully add clarity. Let me know if anything doesn't make sense, and I'm happy to elaborate!
import java.util.Arrays;
import java.util.Scanner;
public class ScannerTestNew {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int[] intArray = new int[3];
int counter = 0;
System.out.println("Start!!");
// Variable used to hold the user's input via the Scanner.
String userInput = null;
while (true) {
System.out.print("Enter an integer: ");
userInput = sc.nextLine();
// Check to see if an empty string/enter/return has been input:
if (userInput.length() == 0) {
System.out.println("Input is empty!");
break;
}
// Checking to see if the input can be parsed into an int. If it can't, retry.
int intInput = 0;
try {
intInput = Integer.parseInt(userInput);
} catch (NumberFormatException e) {
System.out.println("Invalid input for type Integer. Please try again.");
continue;
}
// We know we have an int at this point. Checking that the array isn't already
// filled.
if (counter <= 2) {
intArray[counter] = intInput;
counter++;
// The array is filled, act accordingly.
} else if (counter > 2) {
System.out.println("Array is full.");
System.out.printf("Array Elements: %s", Arrays.toString(intArray));
break;
}
sc.close();
}
}
}

Appropriate InputOutput

Good day, i'm stuck figuring out correct way to implement a function, the function has the following functionality.
1. When program starts, text is displayed to enter a key or leave field empty.
2. If text was entered , do A.
3. If text wasn't entered do B.
This is what i've done so far.
System.out.println("Enter any key to get data or leave empty");
//Just give some value
int value = 0;
try {
for (int i = 5; i > 0; i--) {
System.out.println("Starting in " + i);
Thread.sleep(1000);
//If enter was pressed then theoretically value
//should be 1(Not working)
value = System.in.read();
}
if (value != 0) {
Database.getInstance().getAllStamps();
} else {
start();
}
} catch (Exception e) {
e.printStackTrace();
}

Scanner sc = new Scanner(System.in);
for (int i = 5; i > 0; i--) {
System.out.println("Starting in " + i);
Thread.sleep(1000); // Execution pauses
if(sc.hasNext())
// call your function
break;
}
}
or
boolean flag = false;
for (int i = 5; i > 0; i--) {
System.out.println("Starting in " + i);
Thread.sleep(1000); // Execution pauses
if(sc.hasNext())
flag = true;
}
}
if(flag) {
// call your function
}

One way to get raw input is to use a java.util.Scanner.
Use something like this:
Scanner sc = new Scanner(System.in);
if(sc.hasNext()){
//do stuff with input
}
else{
//handle stuff
}

Make a loop AND catch using Strings instead of ints? (java)

I'm trying to make a text based rock paper scissors. I want the player to choose what they want to play to, for example "best (user response/2 + 1) out of (user response)" then it asks for verification if they would like to play to that number. If they say yes it continues the game with that score, if no it loops back up and lets them choose another number and I have an else that reminds them they can either select yes or no. When they are originally asked, letters don't effect and they are asked to try again. On the second loop around (when you say no) if you enter a String instead of an Int it crashes. Here what I have.
System.out.println("Best of:");
String line = userIn.nextLine();
while (true) {
if (line.length() > 0) {
try { //try catch to stop strings for a response
bestOf = Integer.parseInt(line);
break;
} catch (NumberFormatException e) {
}
}
System.out.println("Please enter a number");
line = userIn.nextLine();
}
System.out.println("Okay, so you want to play best " + (bestOf / 2 + 1) + " of " + bestOf + "?");
String response2 = userIn.nextLine();
while (true) {
if (response2.contains("n")) {
System.out.println("What do you wish to play to then, " + name + "?");
bestOf = userIn.nextInt();
response2 = "y";
} else if (response2.contains("y") || response2.contains("Y")) {
winScore = (bestOf / 2 + 1);
System.out.println("Okay, best " + (bestOf / 2 + 1) + " of " + bestOf + " it is!");
break;
} else {
System.out.println("That's not a valid response! Try again.");
response2 = userIn.nextLine();
}
}

Instead of using parseInt use the string, in other words the input take it as string (even if is a number) them use the function "isNumber" too check if the string the user put is a number if not, do a while
System.out.println("Best of:");
String line = userIn.nextLine();
String aux = line;
do{
if (line.length() > 0)
aux = line;
if(!isNumeric(aux)){
System.out.println("Please enter a number");
line = userIn.nextLine();
}
}while(!isNumeric(aux));
bestOf = Integer.parseInt(aux);
so
public static boolean isNumeric(String str) {
try {
double d = Double.parseDouble(str);
} catch (NumberFormatException nfe) {
return false;
}
return true;
}

You can extract your loop as a method and use it in second case as well.
private Integer readInt(Scanner scanner){
String line = scanner.nextLine();
while (true) {
if (line.length() > 0) {
try { //try catch to stop strings for a response
Integer result = Integer.parseInt(line);
return result;
} catch (NumberFormatException e) {
}
}
System.out.println("Please enter a number");
line = scanner.nextLine();
}
}
or even better:
private Integer readInt(Scanner scanner){
Integer result;
do{
try{
return scanner.nextInt();
} catch (InputMismatchException e){
scanner.nextLine();
System.out.println("Please enter a number");
}
} while (true);
}

Reading from a .txt file

You are given a text file (customer.txt) in which name, lastname and age of customers are stored:
Ali Aslan 25
Ayse Demir 35
Ahmet Gemici 17 .
.
.
You should process this file and find number of customers for each of the following ranges:
0 - 19
20 - 59
60 -
This is my code:
import java.io.*;
import java.util.*;
public class ass11 {
public static void main(String[] args) {
Scanner inputStream = null;
try {
inputStream = new Scanner(new FileInputStream("customer.txt"));
}
catch (FileNotFoundException e) {
System.out.println("file customer.txt not found");
System.exit(0);
}
int next, x = 0, y = 0, z = 0, sum = 0;
while(inputStream.hasNextInt()) {
next = inputStream.nextInt();
sum = sum + next;
if (next >= 60)
x++;
else if (next >= 19 && next <= 59)
y++;
else
z++;
}
inputStream.close();
System.out.println(x + " customer bigger than 60");
System.out.println(y + " customer between 19 and 59");
System.out.println(z + " customers smaller then 19");
}
}
It reads only numbers. When I write a name and surname to the text file, it doesn't work and I don't use the split() method...

I would recommend testing with the original file:
Ali Aslan 25
Ayse Demir 35
Ahmet Gemici 17
Each line is a name plus age, so you would get a code like:
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("path/to/file" ), "UTF-8"));
String line;
while ((line = reader.readLine()) != null) {
String[] contents = line.split(" ");
// Assume contents is 3 long: name, surname, age
System.out.printf("%s %s is %d", contents[0], contents[1], Integer.parseInt(contents[2]));
}
Yes, this does make use of the split method, which makes it easier in my opinion. You could also use the Scanner by calling it in a loop with next(), next() and nextInt()

Try this code. It works.
import java.io.BufferedReader;
import java.io.FileReader;
public class MyProject {
public static void main(String [] args){
String path = "C:/temp/stack/scores.txt";
processTextFile(path);
}
public static void processTextFile(String filePath) {
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(filePath));
String line = br.readLine();
String [] tokens = null;
int score = 0;
int x = 0;
int y = 0;
int z = 0;
while (line != null) {
tokens = line.split(" ");
score = Integer.parseInt(tokens[tokens.length -1]);
if(score >= 0 && score < 20){
x++;
}
if(score >= 20 && score < 60){
y++;
}
if(score > 60){
z++;
}
line = br.readLine();
}
if (br != null) {
br.close();
}
System.out.println("0-20 = " + x + ", 20-60 = " + y + ", 60+ = " + z);
} catch (Exception ex) {
ex.printStackTrace();
}
}
}

Java while loop until user enters a value of 0

Having trouble creating a while loop that continues reading users input values, until the value of 0 is entered. Then the average of all the values will be calculated and printed at the end. Here is part of my coding but this is incorrect. Just showing you the way I perceive the problem.
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
String inputValues;
int sum = 0;
double average;
inputValues = input.readLine();
String[] intValues = inputValues.split("\\s+");
// This is incorrect but this is the idea I am looking for
while(intValues != 0) {
sum += Integer.parseInt(intValues[i]);
}
// Here the average is calculated as a double, and printed below.
average = Double.parseDouble(sum / intValues.length);
System.out.print(average);

You might want to try Scanner here.
Scanner scanner = new Scanner(System.in);
while(scanner.hasNextInt()) {
int num = scanner.nextInt();
if (num == 0)
break;
sum += num;
count += 1;
}
System.out.println("Average: " + sum/count);
For BufferedReader case:
int i = 0;
while(intValues[i] != 0) {// assuming all the number were entered in one line with space as delimiter
sum += Integer.parseInt(intValues[i++]);
}
System.out.println("Average: " + sum/intValues.length);

You could start by using a Scanner class, which will allow you to process the input, for example...
Scanner input = new Scanner(System.in);
int sum = 0;
boolean exit = false;
do {
String input = scanner.nextLine();
Scanner check = new Scanner(input);
if (check.hasNextInt()) {
int value = check.nextInt();
if (value == 0) {
exit = true;
} else {
sum += value;
}
}
} while (!exit);
hasNextInt avoids the possible exception that Integer.parseInt will generate if you try and parse a none-numerical value.
You could also use a while (check.hasNextInt()) {... to loop of multiple input values from a single line of input...
You can check the documentation for Scanner here
If you wish to continue using the BufferedReader, you could use the some stye of logic...
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
int sum = 0;
int count = 0;
double average;
try {
boolean exit = false;
do {
System.out.print(">> ");
String inputValues = input.readLine();
String[] intValues = inputValues.split("\\s+");
for (String value : intValues) {
if ("0".equals(value.trim())) {
exit = true;
break;
} else {
count++;
System.out.println(value);
sum += Integer.parseInt(value);
}
}
} while (!exit);
System.out.println(sum + " / " + count);
average = (double) sum / (double) count;
System.out.print(average);
} catch (IOException exp) {
exp.printStackTrace();
} catch (NumberFormatException exp) {
exp.printStackTrace();
}

Try this
Boolean flag=true;
int counte=0;
while(flag)
{
inputValues = input.readLine();
if(Integer.parseInt(inputValues)==0)
{
flag=false;
continue;
}
counter++; // used to take avarage
sum+=Integer.parseInt(inputValues);
}
And After Loop is finished calculate the avarage