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);
}
Related
public static void main(String[] args) {
i got to enter the amount of names i want, then input them by scanner in console, and after print the longest one, it's mostly done, but i want to print it by JoptionPane aswell
Scanner wczytanie = new Scanner(System.in);
System.out.println("ENTER THE AMOUNT OF NAMES");
int size = wczytanie.nextInt();
String[] array = new String[size];
System.out.println("ENTER THE NAMES");
String name = wczytanie.nextLine();
for (int i = 0; i < array.length; i++) {
array[i] = wczytanie.nextLine();
if (name.length() < array[i].length()) {
name = array[i];
}
}
// System.out.println("LONGEST NAME: " + name);
String name1 = new String();
if(name == name1) {
JOptionPane.showMessageDialog(null, " THE LONGEST NAME IS " + name1);
}
}
You have a lot of problems here: you're reading from the scanner before the loop when reading names and you're doing a raw object equality on a new string for some reason that will never work. You want something more like this:
public static void main(String[] args) {
try (Scanner scanner = new Scanner(System.in)) {
System.out.println("How many names? ");
int num = scanner.nextInt();
List<String> names = new ArrayList<>(num);
System.out.println("Enter names: ");
for (int i = 0; i < num; i++) {
names.add(scanner.next());
}
String longest = names.stream().reduce((a, b) -> a.length() > b.length() ? a : b).get();
System.out.println("The longest name is: " + longest);
JOptionPane.showMessageDialog(null, "The longest name is: " + longest);
}
}
I'm a beginner in Java. I have an assignment that require me to take 3 input from user, then output the 3 at the same time.
here is my code. i have only get 1 output.
suppose look like this:
anyone could help, thx!
here is my code
Scanner sc = new Scanner(System.in);
int i = 0;
String classname = " ";
String rating = " ";
int plus = 0;
while(i < 3){
System.out.print("What class are you rating? ");
classname = sc.nextLine();
System.out.print("How many plus signs does " + classname +" get? ");
rating = sc.nextLine();
plus = Integer.parseInt(rating);
i++;
}
System.out.print(classname + ": ");
while (plus > 0){
System.out.print("+");
plus --;
}
System.out.println();
The very first thing I would do is create a Course POJO (Plain Old Java Object). It should have two fields, name and rating. And I would implement the display logic with a toString in that Course POJO. Like,
public class Course {
private String name;
private int rating;
public Course(String name, int rating) {
this.name = name;
this.rating = rating;
}
public String toString() {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < rating; i++) {
sb.append("+");
}
return String.format("%s: %s", name, sb);
}
}
Then your main method simply involves filling a single array of three Course instances in one loop, and displaying them in a second loop. Like,
Scanner sc = new Scanner(System.in);
Course[] courses = new Course[3];
int i = 0;
while (i < courses.length) {
System.out.print("What class are you rating? ");
String className = sc.nextLine();
System.out.printf("How many plus signs does %s get? ", className);
int classRating = Integer.parseInt(sc.nextLine());
courses[i] = new Course(className, classRating);
i++;
}
i = 0;
while (i < courses.length) {
System.out.println(courses[i]);
i++;
}
You overwrite your variables classname and rating in each loop. You need to store each iteration in a field of an array.
Scanner sc = new Scanner(System.in);
int i = 0;
String[] classname = new String[3]; //create array
String rating = " "; //rating can be overwritten, it is not needed after the loop
int[] plus = new int[3];
while(i < 3){
System.out.print("What class are you rating? ");
classname[i] = sc.nextLine(); //name[index] to read/write fields of an array
//index starts at 0
System.out.print("How many plus signs does " + classname +" get? ");
rating = sc.nextLine();
plus[i] = Integer.parseInt(rating);
i++;
}
for(i = 0;i<3;i++){ //iterate over all elements in the array
System.out.print(classname[i] + ": ");
while (plus[i] > 0){
System.out.print("+");
plus[i] --;
}
System.out.println();
}
I'm new to Java and I'm attempting to learn off different sites and videos and I've been stuck on a problem for a couple of days now and I'm wondering can anyone help out. What I'm trying to do is ask the user how many key actors are in a film. Then i want to ask the actors name and the role they play in the film, this should be asked for each actor for however many the user specified are in the film before finally displaying the actors name and his role?
import java.util.Scanner;
public class rough {
public static void main(String[] args) {
// TODO Auto-generated method stub
int actorCount;
Scanner input = new Scanner(System.in);
Scanner kb = new Scanner(System.in);
System.out.println("How many actors are in the film? ");
actorCount = kb.nextInt();
for (int k = 1; k <= actorCount ; k++)
{
float actor, character;
System.out.println("What is the actors name? ");
actor = kb.nextFloat();
System.out.println("What is " + actor + "'s character?");
character = kb.nextFloat();
System.out.print(actor + " - " + character);
}
kb.close();
input.close();
}
}
This is what I would have done:
import javax.swing.*;
public class rough {
public static void main(String[] args) {
// TODO Auto-generated method stub
int actorCount;
String output = "";
actorCount = Integer.parseInt(JOptionPane.showInputDialog(null,"How many actors are in the film? "));
for (int k = 1; k <= actorCount ; k++)
{
String actor, character;
actor = JOptionPane.showInputDialog(null, "What is the actors name?");
character = JOptionPane.showInputDialog(null, "What is " +actor + "s character?");
output += actor + " - " + character + "\n";
}
JOptionPane.showMessageDialog(null, output);
}
}
Remember that if you want all of the roles/actors to be printed at the same time you must put the print outside the for loop and store the roles/actors to some output String. Moreover, I cannot see why you have used a float variable for the roles/actors a String would be the most logical.
So you should do it in this way:
public static void main(String[] args) {
int actorCount;
Scanner input = new Scanner(System.in);
Scanner kb = new Scanner(System.in);
System.out.println("How many actors are in the film? ");
actorCount = kb.nextInt();
String[][] actorValues = new String[actorCount][2];
for (int k = 0; k < actorCount ; k++)
{
String actor, character;
System.out.println("What is the actors name? ");
actor = kb.next();
System.out.println("What is " + actor + "'s character?");
character = kb.next();
System.out.print(actor + " - " + character +"\n");
actorValues[k][0] = actor;
actorValues[k][1] = character;
}
//Printout the Characters in the List
System.out.println("All Actors:");
for (int i = 0; i < actorValues.length; i++) {
String[] strings = actorValues[i];
System.out.println("Actorssname: "+strings[0]+" Character:"+strings[1]);
}
kb.close();
input.close();
}
This is probably very basic stuff, but I am not too sure how I should ask questions because I am very new to this, so here goes.
I am practicing vectors and what we can do to them. I have prompted the user for the elements of the vectors (per my directions) among other things successfully. For my next step, I have to "print out the element at index i in each of the two vectors." I was given the methods which I am supposed to use, but the explanations I saw of them were very unclear. Here they are:
Object get (int which)
Object remove (int which)
set (int index, object element)
How would I get the system output to be the element at the index i?
package vectorusage;
import java.util.*;
public class VectorUsage {
public static void main(String[] args) {
Vector a = new Vector ();
Vector b = new Vector ();
System.out.println (a);
System.out.println (b);
Scanner input = new Scanner(System.in);
String first;
System.out.print("Please enter 4 strings.");
first = input.next();
a.add (first);
String second;
second = input.next();
a.add (second);
String third;
third = input.next();
a.add (third);
String fourth;
fourth = input.next();
a.add (fourth);
String fifth;
System.out.print("Please enter 4 more strings.");
fifth = input.next();
b.add (fifth);
String sixth;
sixth = input.next();
b.add (sixth);
String seventh;
seventh = input.next();
b.add (seventh);
String eighth;
eighth = input.next();
b.add (eighth);
System.out.println("Vector a is size " + (a.size()) + " and contains: " + (a));
System.out.println("Vector b is size " + (b.size()) + " and contains: " + (b));
int i;
System.out.println("Please enter an integer.");
i = input.nextInt();
System.out.println("Element at index " + i + " in Vector a is: " + ;
Avoid using vectors, they are deprishiated. Use ArrayList instead.
Using a for loop you can simplify your code like below,
(Please note, this code does not validate user input or do error handling)
import java.util.ArrayList;
import java.util.Scanner;
public class Test {
public static void main(String args[]) {
Scanner input = new Scanner(System.in);
ArrayList<Integer> numbers = new ArrayList<Integer>();
System.out.println("Please enter 8 strings.");
for(int i = 1; i <= 8; i++) {
System.out.print("Please enter strings #" + i + ": ");
numbers.add(input.nextInt());
}
for(int j = 0; j < numbers.size(); j++) {
System.out.println("Number at index " + j + " is " + numbers.get(j));
}
}
}
I usually use a mix of while and for loop. The while loop is used to add the user input into the vector. The for loop prints out the elements of the vector using index i. I've set it to print all the elements of the vector but you can modify it by using if conditions. Here's my code, hope it helps!
import java.util.*;
import java.io.*;
public class VectorUsage {
public static void main(String[]args) {
Scanner input=new Scanner(System.in);
Vector a=new Vector();
int count =0;
while(count<4)
{
System.out.print("Enter a string: ");
a.addElement(input.nextLine());
count++;
}
for(int i=0;i<a.size();i++)
{
System.out.println(a.elementAt(i));
}
Vector b=new Vector();
int count1=0;
while(count1<4)
{
System.out.print("Enter a string: ");
b.addElement(input.nextLine());
count1++;
}
for(int i=0;i<b.size();i++)
{
System.out.println(b.elementAt(i));
}
}
}
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)));