This question already has answers here:
How to append elements at the end of ArrayList in Java?
(4 answers)
Closed last year.
public void getDisMarks()
{
marks=new int[3];
System.out.print("Enter marks of Physics: ");
marks[0]=sc.nextInt();
System.out.print("Enter marks of Chemistry: ");
marks[1]=sc.nextInt();
System.out.print("Enter marks of Maths: ");
marks[2]=sc.nextInt();
}
So in this piece of code we are using array for 3 definite subjects. And we're using scanner class to input from the user. Let's say in the future I want to add a couple of more subject. So coding it again would not make it any flexible.
So I read that we could use arrayList, How can I use scanner class with arrayList similar to this piece of code.
You could do something like this:
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
List<Integer> list = new ArrayList<>();
System.out.println("How many marks to enter?");
int marksToEnter = sc.nextInt();
for (int i = 0; i < marksToEnter; i++) {
System.out.println("Enter next mark");
list.add(sc.nextInt());
}
System.out.println(list);
}
Related
This is just some homework but I cannot find a way to achieve it like I want. Have a look at my code please.
Once the numbers are typed, I'd just like to play around with them.
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
//user says if he'd like to use 3 numbers for instance (2,4,5)
System.out.println("How many numbers would you like to use? : ");
int amountOfNumbers = sc.nextInt();
System.out.println("Great! Please type in your numbers: ");
int numbers =sc.nextInt(amountOfNumbers);
// should let him write the amount of numbers he entered
}
Once he has typed the amount of numbers he'd like to use, I would like the scanner to give him the possibility to type in all of those numbers.
Let's say he the amount of numbers he'd like to use is three.
I would like him to be able to type it in the console like this:
First number + enter key
Second number + enter key
Third number + enter key
Not able to write anymore
That is what I meant here by adding "amountOfNumbers" in the scanner itself... (which is not working)
int numbers =sc.nextInt(amountOfNumbers);
BR
Consider a for loop:
for(int i = 0; i < amountofNumbers; i++){
// add to a collection / array / list
}
And then access what you need from there.
import java.util.*;
class EnterNumber{
public void enter_list_function(){
Scanner sc = new Scanner(System.in);
System.out.println("How many numbers would you like to use?");
//Enter the Numbers of amount
int input = sc.nextInt();
ArrayList<Integer> list = new ArrayList<Integer>();
System.out.println("Great! Please type in your numbers: ");
//Input - Numbers of amount
for(int j =1; j<=input; j++ ){
int addval = sc.nextInt();
//Add the enter amount in array
list.add(addval);
}
Iterator itr=list.iterator();
while(itr.hasNext()){
//get the enter amount from list
System.out.println(itr.next());
}
}
public static void main(String[] args){
EnterNumber EnterNumber = new EnterNumber();
EnterNumber.enter_list_function();
}
}
I have a For Loop and it's asking the user how many times the loop should be looped inside the loop. How do I loop it the number of times given without repeating the question "how many names would you like to input"?
The issue is that I don't want to repeat the question after the user answered it. When the user answers the question, I want it to ask for the names x amount of times and then move on.
The main problem is that I need to ask how many times to loop it after the name is asked. It's says it the assignment sheet.
Thanks so much!
for (int i = 0; i < num; i++) {
System.out.println("Enter name #" + (i+1));
names[i] = input.next();
System.out.println("How many names would you like to input?");
num = input.nextInt;
}
You must move your num getter code outside of loop like this:
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("How many names would you like to input?");
int num = input.nextInt();
String names[] = new String[num];
for (int i = 0; i < num; i++) {
System.out.println("Enter name #" + (i+1));
names[i] = input.next();
}
}
Always move these kinds of questions out of the loop rather than inside.
System.out.println("How many names would you like to input?");
num = input.next();
for (int i = 0; i < num; i++) {
System.out.println("Enter name #" + (i+1));
names[i] = input.next();
}
num = input.next();
You are asking a numbers not a string should change the .next() to either nextInt or nextShort.
#DevilsHnd the first code won't work indeed, I never saw that String [] = new String [] use array before plus this will explain better why.
#J.A.P link with code may work
import java.util.Scanner;
public class Newpro{
public static void main(String args[]){
Scanner sc = new Scanner(System.in);
System.out.println("how many times you want to loop?")
int num = sc.nextInt();//input the no of times you want to loop
String names[i] = new String[num];//initialize a string array for reading names
for(i=0;i<num;i++){
System.out.println("enter name#"+(i+1));
names[i]=sc.next();
}
for(j=0;j<num;j++){
//printing the names entered by you
System.out.println("the entered names by you are"+" "+names[j]);
}
as others suggested, you have to move your 'num' getter part out of the loop and after that initialize a string array for reading your names by specifying how many names you want to enter(index of string array = number of names you want to enter and no of times you want to loop as well==>'num') and based on that number the looping will be done with above code.
finally iterate through the array and print the names entered by you.
Edit:1
check with the below code if you need to ask "how many names user wants to input AFTER it asks for a first name.
import java.util.Scanner;
public class Newpro2{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
//make sure you create a string array with index = no of names you want to
//enter
String[] names = new String[10];
System.out.println("enter name#1");
names[0]= sc.next();
System.out.println("how many inputs you want to give?");
num=sc.nextInt();//give the no of inputs you want to give here
//read the remaining names
for(int i=1;i<num;i++){
System.out.println("enter name#"+(i+1));
names[i] = sc.next();
}
//print all the names entered by you
for(int j=0;j<num;j++){
System.out.println("entered name#"+(j+1)+"by you is"+" "+names[j]);
}
This question already has answers here:
Scanner is skipping nextLine() after using next() or nextFoo()?
(24 answers)
Closed 4 years ago.
I was trying to take input for the number of names to be stored in an array from user and then using that i was taking names from the user ,first i tried to take names from the user using next() method and all the things were fine but when i tried to take input using nextLine() method the output was as shown below
package learningJava;
import java.util.Scanner;
public class practice
{
public static void main(String[] args)
{
int n;
Scanner obj = new Scanner(System.in);
System.out.println("Enter the number of names you are gonna enter");
n = obj.nextInt();
String names[] = new String[n];
for(int i=0;i<n;i++)
{
System.out.println("Enter the name of friend "+(i+1));
names[i]=obj.nextLine();
}
obj.close();
System.out.println("Names of your friends are");
for(int i=0;i<names.length;i++)
{
System.out.println(names[i]);
}
}
}
Output for the nextLine() method
Enter the number of names you are gonna enter
5
Enter the name of friend 1
Enter the name of friend 2
It is not prompting me to enter the name of friend 1 and directly skipping it and coming to the friend 2 line.
I am beginner in Java , i know the basic difference in next and nextLine() that next() doesn't take input after a space but nextLine() takes complete input , So what is happening here ??
just in for loop, just change "println" to "print" because nextLine() consumes new line character.
import java.util.Scanner;
public class practice
{
public static void main(String[] args)
{
int n;
Scanner obj = new Scanner(System.in);
System.out.println("Enter the number of names you are gonna enter");
n = obj.nextInt();
String names[] = new String[n];
for(int i=0;i<n;i++)
{
System.out.print("Enter the name of friend "+(i+1));
names[i]=obj.nextLine();
}
obj.close();
System.out.println("Names of your friends are");
for(int i=0;i<names.length;i++)
{
System.out.println(names[i]);
}
}
}
check this answer: Java String Scanner input does not wait for info, moves directly to next statement. How to wait for info?
This question already has answers here:
How do I print my Java object without getting "SomeType#2f92e0f4"?
(13 answers)
Closed 7 years ago.
I am writing a program that the main method asks the user for how many numbers they want in an array, then asks them to input that many numbers, and stores them in initialArray. In another method reverseTheArray, a NEW array is created that stores the elements of initialArray in reverse order. The method is called in main and prints the reversed array. No matter what input, the string "[I#33909752" is printed at the end. What is this and how do I get rid of it?
import java.util.Scanner;
public class Reverse {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("How many numbers do you want in your array?: ");
int num = scan.nextInt();
int[] initialArray = new int[num];
System.out.println("Please enter your numbers into the array: ");
for(int i=0; i<num; i++){
initialArray[i] = scan.nextInt();
}
System.out.println(reverseTheArray(initialArray));
}
public static int[] reverseTheArray (int[] initialArray){
int[] reversedArray = new int[initialArray.length];
for(int j=0; j<reversedArray.length; j++){
reversedArray[j] = initialArray[initialArray.length-1-j];
System.out.print(reversedArray[j]+" ");
}
return reversedArray;
}
}
You're seeing the default toString() from an array. To see the array items themselves you could use the java.util.Arrays toString(...) method like so:
System.out.println(java.util.Arrays.toString(reverseTheArray(initialArray)));
This question already has answers here:
Scanner is skipping nextLine() after using next() or nextFoo()?
(24 answers)
Closed 7 years ago.
I am trying to create a simple String Revert program that does the following:
Prompts the user for an integer n
Creates an array of n Strings
Keeps reading character strings from user and stores them in the array, until the end of the array or user types "quit"
Prints the strings from the array in reverse order excluding empty slots
Here is my attempt so far:
-However, when i take input and make the size 4, the buffer only reads 3 strings and stops rather than 4.
import java.util.*;
import java.io.*;
class StringRevert {
public static void main(String[] args) {
String myArray[];
Scanner Scan = new Scanner(System.in);
System.out.println("Enter Number: ");
int size = Scan.nextInt();
myArray = new String[size];
for(int i=0; i<myArray.length; i++) {
myArray[i] = Scan.nextLine();
}
}
}
You need to put Scan.nextLine(); before starting of for loop.
public static void main(String[] args) {
String myArray[];
Scanner Scan = new Scanner(System.in);
System.out.println("Enter Number: ");
int size = Scan.nextInt();
myArray = new String[size];
Scan.nextLine();
for(int i=0; i<myArray.length; i++) {
System.out.println("Enter String");
myArray[i] = Scan.nextLine();
}
}