As the title said I need to enter a string "Enter a number: " repeat itself after I've entered multiple values until I enter "DONE."
So for example it should look like this:
Enter a number:
4
Enter a number:
53
Enter a number:
DONE //closes program
This is a small part to a larger program and granted I know its simple, but I cant figure this out :[
What I'm guessing and been trying is a public static class with a toString method. But I can only get one "Enter a number: " printed once.
Enter a number:
4
53
DONE //closes program
Thanks in advance.
Some code I have for this part would be:
import java.util.Scanner;
public class EnterANumba
{
public static void main(String[] args)
{
while() //Stuck here
{
System.out.println("Enter a number:");
}
Scanner scanner = new Scanner(System.in);
String word=null;
while (scanner.hasNextLine())
{
word = scanner.nextLine();
if (word != null)
{
word = word.trim();
if (word.equalsIgnoreCase("done"))
{
break;
}
}
else
{
break;
}
}
I guess this following code snippet may help you.
public class Main {
public static void main(String[] args) {
Scanner s=new Scanner(System.in);
System.out.println("Enter a number:");
while(!(s.next().equalsIgnoreCase("DONE"))){
System.out.println("Enter a number:");
}
}
}
try asking for the 1st time and then make a loop where you validate the input and ask until the condition is met...
Example:
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Please enter a number:");
while (!("done".equalsIgnoreCase(scanner.next()))) {
System.out.println("Enter a number:");
}
System.out.println("Enter a number:we are done....");
}
Related
Im trying to ask the user for two numbers. I want to check if those inputs are in fact numbers but the code I have so far does not let me enter a second value if the first input is a string.
So the scanner does not read anything the else statement.
How could I make it work?
import java.util.Scanner;
public class calculations {
public static void main(String[] args) {
Scanner console = new Scanner(System.in);
System.out.print("Please enter your first name: ");
String fname = console.nextLine();
System.out.print("Please enter your last name: ");
String lname = console.nextLine();
System.out.print("Please enter your first number: ");
if (console.hasNextInt()) {
int number1 = console.nextInt();
System.out.print("Please enter your second number: ");
if (console.hasNextInt()) {
int number2 = console.nextInt();
}
} else
System.out.print("Please enter your second number: ");
if (console.hasNextInt()) {
int number2 = console.nextInt();
// this part does not work
}
}
}
You just need to add console.nextLine(); after your else statement, because the Scanner.hasNextInt method does not move cursor past your previous input (if it is a string).
I amm at my very beginning at java and just wanted to ask.
I want to ask the user to put Yes/No to a question and proceed to the next question. How do I do it?
import java.util.Scanner;
public class sff {
public static void main (String args[]) {
System.out.println("Hello There! We want to ask you some questions! but first: ");
System.out.print("Enter your age: ");
Scanner in = new Scanner(System.in);
int num = in.nextInt();
int age = num;
if( age == 12){
System.out.println("Hello Dan, I know you very well! ");
}
{
System.out.println("First question: ");
System.out.println("Do you exercise?(Yes/No) ");
// how do i proceed from here??
Use Scanner and get next line, then check if that line is yes or no then handle respectively.
In the example below, I used a while loop to keep asking them to input yes or no in case they enter something different like "maybe".
For example:
Scanner in = new Scanner(System.in);
// Loop until they enter either yes or no.
while(true){
String line = in.nextLine();
// Use this to check if it is yes or no
if(line.equalsIgnoreCase("yes")){
// Process yes
break;
}else if(line.equalsIgnoreCase("no")){
// Process no
break;
}else{
// Tell them to enter yes or no since they entered something else.
}
}
Are you looking for something like this?
//import to use the Scanner
import java.util.Scanner;
public class Stack_Overflow_Example {
public static void main(String[] args) {
System.out.println("First question: ");
System.out.print("Do you exercise?(Yes/No) ");
Scanner in = new Scanner(System.in);
//get the user input and store it as a String
String exerciseQuestion = in.nextLine();
//check what the user said.
if(exerciseQuestion.equalsIgnoreCase("yes")){
System.out.println("Dan does exercise");
//do you code when he exercises
}
else{
System.out.println("Dan does not exercise");
//do your not exercise code here
}
System.out.println("Ask your next question so on....");
}//main
}//class
If you want to deal with answers other than yes/no you can use this code:
import java.util.Scanner;
public class Stack_Overflow_Example {
public static void main(String[] args) {
System.out.println("First question: ");
System.out.print("Do you exercise?(Yes/No) ");
Scanner in = new Scanner(System.in);
String exerciseQuestion;
while (true){
//get the user input
exerciseQuestion = in.nextLine();
//check if user input is yes or no
if((exerciseQuestion.equalsIgnoreCase("yes")) ||
exerciseQuestion.equalsIgnoreCase("no"))
//if yes break and continue with your code
break;
else
//else loop back to get user input until answer is yes/no
System.out.println("Please answer with yes or no only");
}//while . i.e answer not yes or no
if(exerciseQuestion.equalsIgnoreCase("yes")){
System.out.println("Dan does exercise");
//do your code
}
else{
System.out.println("Dan does not exercise");
//do your not exercise code here
}//else
}//main
}//class
I just want the scanner to read new line as empty string then continue to next process if the user press enter. So valid input must be y,n,enter. Any idea how to do this?
This is my code:
String gender = "", employed = "";
Scanner in = new Scanner(System.in);
System.out.print("Gender M/F, press enter to skip... ");
while(!in.hasNext("[mfMF]$")){
System.out.print("Invalid, please choose m/f only... ");
in.nextLine();
}
if(in.hasNextLine()){
gender = in.nextLine();
}
System.out.print("Employed? y/n, press enter to skip... ");
while(!in.hasNext("[ynYN]$|")){
System.out.print("Invalid, please choose y/n only... ");
in.nextLine();
}
if(in.hasNextLine()){
employed = in.nextLine();
}
System.out.println(gender + " : " + employed);
Try This :
import java.util.*;
class Scanner1
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
String s;
do
{
s=sc.nextLine();
if(!(s.equalsIgnoreCase("y")||s.equalsIgnoreCase("n")||s.equalsIgnoreCase("")))
{
System.out.println("Please Enter valid input");
}
}while(!(s.equalsIgnoreCase("y")||s.equalsIgnoreCase("n")||s.equalsIgnoreCase("")));
}
}
So, to check if the user has pressed enter, you would have to make use of the isEmpty() method. The way to do that is shown below:
String enter = in.nextLine();
if (enter.isEmpty()) {
// do what is needed
}
So I'm trying to use if-else statement dependant upon the user's input. It works when the user's input is only one word, however, multiple word inputs go unrecognized and triggers the else statement. How can i resolve this?
import java.util.Scanner;
public class MyFirstJavaClass {
public static void main(String[] args) {
#SuppressWarnings("resource")
Scanner myScanner = new Scanner(System.in);
String answer;
System.out.println("Catch the tiger or run away?");
answer = myScanner.next();
if (answer.equals("Catch the tiger" )) {
System.out.println("You've been mauled by a tiger! What were you thinking?");
answer = myScanner.next();
} else {
System.out.println("run away");
}
}
}
Replace:
answer = myScanner.next();
With:
answer = myScanner.nextLine();
next will only read in the next value until it reaches a space or newline. You want to read in the full line before making the comparison
try this :
Scanner scanner = new Scanner(System.in);
int choice = 0;
while (scanner.hasNext()){
if (scanner.hasNextInt()){
choice = scanner.nextInt();
break;
} else {
scanner.next(); // Just discard this, not interested...
}
}
Reference :
Flush/Clear System.in (stdin) before reading
Try this
import java.util.Scanner;
public class MyFirstJavaClass {
public static void main(String[] args) {
#SuppressWarnings("resource")
Scanner myScanner = new Scanner(System.in);
System.out.println("Catch the tiger or run away?");
if (myScanner.hasNext("Catch the tiger")) {
System.out.println("You've been mauled by a tiger! What were you thinking?");
} else {
System.out.println("run away");
}
}
}
import java.util.Scanner;
public class test {
public static void main(String[] args) {
System.out.print("Enter a number: ");
Scanner keyboard = new Scanner(System.in);
int x = keyboard.nextInt();
}
}
How do I loop a piece of code like the one above until an int is entered instead of giving an error when a non-int is entered?
The Scanner class has a lot of stuff built in so that you don't need to do try-catches unless you are explicitly looking to catch the errors.
public static int test(){
int number = 0;
Scanner input = new Scanner(System.in);
boolean valid = false;
do{
System.out.print("Please enter an integer: ");
if(input.hasNextInt()){ // This checks to see if the next input is a valid **int**
number = input.nextInt();
valid = true;
}
else{
System.out.print("Not a valid integer!\n");
input.next();
}
}while(valid == false);
return number;
}
This tries to run the scanner, if a input is one that is not expected it will simply restart. You can add a message to it, my code was for brevity.
import java.util.Scanner;
public class test {
public static void main(String[] args) {
System.out.print("Enter a number: ");
Scanner keyboard = new Scanner(System.in);
try {
int x = keyboard.nextInt();
}
catch (java.util.InputMismatchException e) {
main(null);
}
}
}