I need to write a program that uses a bubble sorting method and main function that asks for a user to input their array. After which the program sorts the array in ascending order. My program right now asks the for the user's input, but once that happens, the program won't compile and I'm stuck. Here's the code:
import java.util.Scanner;
public class IntSorter{
public static int bubbleSort(int[] a){
boolean needNextPass =true;
for(int i=1; i<a.length && needNextPass; i++){
needNextPass = false;
for(int j=0; j<a.length - i; j++){
if(a[j]> a[j+1]){
int temp = a[j];
a[j]=a[j+1];
a[j+1] = temp;
needNextPass = true;
}
}
}
for(int i=0; i<a.length; i++){
System.out.print(a[j] + " ");
}
}
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.print("Enter size of array: ");
int N = input.nextInt();
int[] x = new int[N];
System.out.print("Enter " +N +"numbers of your array: ");
for(int i= 0; i<N; i++){
x[i] = input.nextInt()
}
IntSorter access = new IntSorter();
System.out.print("Your sorted array is: ");
access.IntSorter(x);}
}
You last line in your main method is : -
access.IntSorter(x);
Replace this line with: -
access.bubbleSort(x);
And using single uppercase character as variable is terrible.. use size instead for size of array..
System.out.print("Enter " +N +"numbers of your array: ");
for(int i= 0; i<N; i++){
x[i] = input.nextInt()
}
And in the above code, what if user didn't enter an integer value?? You will get an exception.. You need to catch that..
This line seems to be missing a semicolon:
x[i] = input.nextInt()
And you seem to be access a variable j outside of its scope:
System.out.print(a[j] + " ");
You could use i instead of j which is undefined:
for (int i = 0; i < a.length; i++) {
System.out.print(a[i] + " ");
}
Also
public static int bubbleSort(int[] a) {
has no int return value;
You can use your compiler or IDE to help highlight these issues.
Related
Complete question is: Create a program that uses a two dimensional array that can store integer values inside. (Just create an array with your own defined rows and columns). Make a method called Square, which gets each of the value inside the array and squares it. Make another method called ShowNumbers which shows the squared numbers.
What I attempted thou it has errors:
public class SquareMatrix {
public static void main(String[] args) {
int sqr[][]= {{1,3,5},{2,4,6}};
System.out.println("Your Original Matrix: ");
for(int i = 0; i < 2; i++){
for(int j = 0; j < 3; j++){
System.out.print(sqr[i][j] + " ");
}
System.out.println();
}
Square();
ShowNumbers();
}
static void Square(){
for(int i = 0; i <= 1; i++) {
for(int j = 0; j <= 2; j++) {
sqr[i][j] = sqr[i][j] * sqr[i][j];
}
}
}
static void ShowNumbers(){
System.out.println("Matrix after changes: ");
for(int i = 0; i < 2; i++){
for(int j = 0; j < 3; j++){
System.out.print(sqr[i][j] + " ");
}
System.out.println();
}
}
}
Also how would I write it if I wanted an input from the user for the col and row for a specific range of 0 to 10, I made an alternative version with many errors below. Below code is not as important as the one above
import java.util.Scanner;
public class MyClass {
public static void main(String args[]) {
int row, col, i, j;
int arr[][] = new int[10][10];
Scanner scan = new Scanner(System.in);
try{
System.out.print("Enter Number of Row for Array (max 10) : ");
row = scan.nextInt();
System.out.print("Enter Number of Column for Array (max 10) : ");
col = scan.nextInt();
if(0>=row && row<=10 || 0>=col && col<=10 ){
}
}
catch (Exception e){
System.out.println("(!) Wrong input...\n");
}
System.out.print("Enter " +(row*col)+ " Array Elements : ");
for(i=0; i<row; i++){
for(j=0; j<col; j++){
arr[i][j] = scan.nextInt();
}
}
}
static void square(){
arr[row][col] = arr[row][col] * arr[row][col];
}
static void ShowNumbers(){
System.out.print("The Array is :\n");
for(i=0; i<row; i++)
{
for(j=0; j<col; j++)
{
System.out.print(arr[i][j]+ " ");
}
System.out.println();
}}}
PS I am new to java and would appreciate a response with the whole code pasted not just a section of the code so I don't get lost or with the number of the line the error is from.
thanks for any help
Since you are starting from scratch, it would be good to go over the basics of the language again. Take a look at oracle classvars For your upper problem you need to understand the difference between local and instance variables and the difference between static and non static variables respectively. To solve your issue just move the declaration of your array out of the main method and add a static modifier:
public class SquareMatrix {
static int sqr[][] = {{1, 3, 5}, {2, 4, 6}};
public static void main(String[] args) {
//rest of your code
}
I have a question about stop array input limit then the result to show the output.
Below is my coding have already set new float[3][3]:
import java.util.Scanner;
public class Clone2Darray {
public static float[][] clone(float[][] a) throws Exception {
float b[][] = new float[a.length][a[0].length];
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[0].length; j++) {
b[i][j] = a[i][j];
}
}
return b;
}
public static void main(String args[]) {
Scanner sc = new Scanner (System.in);
System.out.println ("Type nine float numbers two-dimensional array of similar type and size with line breaks, end by -1:");
float[][] a = new float[3][3];
for (int i=0; i<3; i++){
for (int j=0; j<3; j++){
String line = sc.nextLine();
if ("-1".equals(line)){
break;
}
a[i][j]=Float.parseFloat(line);
}
}
System.out.println("\n The result is:");
try {
float b[][] = clone(a);
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[0].length; j++) {
System.out.print(b[i][j] + " ");
}
System.out.println();
}
} catch (Exception e) {
System.out.println("Error!!!");
}
}
}
The limit output is show me like below:
run:
Type float numbers in the two-dimensional array of similar type and size
with line breaks, end by -1:
5.33
9.33
63.33
6.36
3.55
7.25
2.33
3.66
The result is:
6.33 5.33 9.33
63.33 6.36 3.55
7.25 2.33 3.66
BUILD SUCCESSFUL (total time: 31 seconds)
My problem is want to stop limit float[3][3] and can unlimited key in the input until type -1 to stop the input. May I know how to remove the limit float[3][3] in the array? Hope anyone can guide me to solve my problem. Thanks.
At the point when you allocate memory for the two-dimensional array you have to tell the sizes of its elements, because memory will be allocated for that array and the amount of memory to be allocated must be known.
You can bypass this, by using some more dynamic types, like List and its popuplar implementation, ArrayList, even in a nested form. That's a nice thing to do, but then you will not have a "real" array.
The below code allows you to create the dynamic arrays.
import java.util.Scanner;
public class Clone2DArray {
public static float[][] clone(float[][] a) throws Exception {
float b[][] = new float[a.length][a[0].length];
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[0].length; j++) {
b[i][j] = a[i][j];
}
}
return b;
}
public static void main(String args[]) {
Scanner sc = new Scanner (System.in);
System.out.println("enter row size");
int row = Integer.parseInt(sc.nextLine());
System.out.println("enter column size");
int column = Integer.parseInt( sc.nextLine());
System.out.println ("Type float numbers two-dimensional array of similar type and size with line breaks:");
float[][] a = new float[row][column];
for (int i=0; i<row; i++){
for (int j=0; j<column; j++){
String line = sc.nextLine();
if ("-1".equals(line)){
break;
}
a[i][j]=Float.parseFloat(line);
}
}
System.out.println("\n The result is:");
try {
float b[][] = clone(a);
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[0].length; j++) {
System.out.print(b[i][j] + " ");
}
System.out.println();
}
} catch (Exception e) {
System.out.println("Error!!!");
}
}
}
I'm trying to write a program where on the first line, you enter the number of times you want a for loop to iterate, on the second line, you enter the value of the array, and on the third line, you enter the numbers that you want in the array. My program either does not do what I want it to do, or it crashes on me. This is the code that I have for the program so far:
import java.util.*;
public static void main(String[] args) {
Scanner input = new Scanner (System.in);
int n = input.nextInt();
for (int i=0; i<n; i++)
{
int value = input.nextInt();
int[] arr = new int[value];
arr[i] = input.nextInt();
}
}
What can I do? Please help. I've tried everything! Also, it would help if someone could help me with sorting the numbers in ascending order, followed by displaying the middle number in each line, but first thing's first. Thank you.
I believe this is more of what you are after. I output the entries individually but you could combine that easily enough.
public static void main(String[] args)
{
Scanner input = new Scanner (System.in);
try
{
System.out.println("Number of times to loop:");
int numEntries = input.nextInt();
int[][] valueArrays = new int[numEntries][];
for (int i=0; i<numEntries; i++)
{
System.out.println("Size of array #"+i+": ");
int arrayLen = input.nextInt();
int[] inputArray = new int[arrayLen];
for (int j = 0; j < arrayLen; j++)
{
System.out.println("Enter value at index "+j+": ");
inputArray[j] = input.nextInt();
}
Arrays.sort(inputArray);
valueArrays[i] = inputArray;
}
for (int l=0; l < valueArrays.length; l++)
{
int[] values = valueArrays[l];
for (int m=0; m < values.length; m++)
{
System.out.println("Value of array #"+l+" saved at index "+m +": " + values[m]);
}
if ((values.length % 2) == 0)
{
int start = values.length/2;
int end = start + 1;
System.out.println("Middle values in array #"+l+" saved at indices " + start + " and " + end);
}
else
{
int start = values.length/2;
System.out.println("Middle value in array #"+l+" saved at index " + start);
}
}
}
finally
{
input.close();
}
}
You're creating a new array on each iteration inside the loop.
You should get int[] arr = new int[value]; out of the loop:
int arraySize = input.nextInt();
int[] arr = new int[arraySize];
for (int i=0; i<arraySize; i++)
{
int value = input.nextInt();
arr[i] = value;
}
If you don't want to limit the user for a size, use an ArrayList instead.
Problem 1:My program either does not do what I want it to do.
Dont initialize array inside for loop as loop wiil create a new array every time you iterate it.
Scanner input = new Scanner (System.in);
System.out.println("Enter no. of elements in array");
int n = input.nextInt();
int[] arr = new int[n];
System.out.println("Array length set to "+n);
for (int i=0; i<n; i++)
{
System.out.println("Enter value for index "+i);
arr[i] = input.nextInt();
System.out.println(arr[i]+" Value saved at index "+i);
}
DEMO1
Problem 2(described in comments below):Sorting arrays and displaying the middle number
class Ideone
{
static int[] countingSort(int[] numbers) {
int max = numbers[0];
for (int i = 1; i < numbers.length; i++) {
if (numbers[i] > max)
max = numbers[i];
}
int[] sortedNumbers = new int[max+1];
for (int i = 0; i < numbers.length; i++) {
sortedNumbers[numbers[i]]++;
}
int insertPosition = 0;
for (int i = 0; i <= max; i++) {
for (int j = 0; j < sortedNumbers[i]; j++) {
numbers[insertPosition] = i;
insertPosition++;
}
}
return numbers;
}
public static void main (String[] args) throws java.lang.Exception
{
Scanner input = new Scanner (System.in);
System.out.println("Number of times to loop:");
int n = input.nextInt();
// int[] arr = new int[n];
// System.out.println("Array length set to "+n);
for (int i=1; i<=3; i++)
{
System.out.println("Size of array #"+i+": ");
int alen = input.nextInt();
int[] arr = new int[alen];
System.out.println("Value in array #"+i+": ");
for (int j=0; j<alen; j++){
System.out.println("Enter value at index "+j+": ");
arr[j] = input.nextInt();
}
arr=Ideone.countingSort(arr);
for (int l=0; l<alen; l++)
System.out.println(arr[l]+" Value of array #"+i+" saved at index "+l);
System.out.println("Middle value in array #"+i+" saved at index "+arr[alen/2]);
}
}
}
DEMO2
I have this code and I do not know why the selection sort is not sorting all the way Does anyone know where to fix the program. The selection sort code I believe is right i just dont know what is wrong. The code is functioning
import java.util.Scanner;
public class selectionSort
{
public static void main(String[] args)
{
Scanner scanner = new Scanner(System.in);
int temp;
int i,j,first;
System.out.println("How many numbers do you want to enter?");
int ammount = scanner.nextInt();
int[]array = new int[ammount];
for (i = 0 ; i < array.length; i++ )
{
System.out.println("Enter the numbers now.");
array[i] = scanner.nextInt();
}
System.out.println("\nThe array is:");
for(i = 0; i < array.length; i++){
System.out.print(array[i] + " ");
}
for (i=array.length - 1; i>0;i--)
{
first=0;
for(j=1;j<=1;j++)
{
if(array[j]<array[first])
first = j;
}
temp = array[first];
array[first] = array[i];
array[i]=temp;
}
System.out.println("\nThe sorted array is:");
for( i = 0; i < array.length; i++){
System.out.print(array[i] + " ");
}
}
}
You appear to have a typo. This line:
for(j=1;j<=1;j++)
should probably be:
for(j=1;j<=i;j++)
(The loop termination test should be j<=i, not j<=1.)
Hi i am trying to auto populate a 2d array based on user input.
The user will enter 1 number, this number will set the size of the 2d array. i then want to print out the numbers of the array.
for example , if the user enters the number 4 . the 2d array will be 4 rows by 4 colums, and should contain the number 1 to 16, and print out as follows.
1-2-3-4
5-6-7-8
9-10-11-12
13-14-15-16
But i am struggling to think of the right statement that will do this.
for the moment my code just prints out a 2d array containing *.
Has anyone any ideas how i could print out the numbers , i'm really stuck.
my code follows:
public static void main(String args[]){
Scanner input = new Scanner(System.in);
System.out.println("Enter room length");
int num1 = input.nextInt();
int num2 = num1;
int length = num1 * num2;
System.out.println("room "+num1+"x"+num2+"="+length);
int[][] grid = new int[num1][num2];
for(int row=0;row<grid.length;row++){
for(int col=0;col<grid[row].length;col++){
System.out.print("*");
}
System.out.println();
}
}
Read n value,
int[][] arr = new int[n][n];
int inc = 1;
for(int i = 0; i < n; i++)
for(int j = 0; j < n; j++)
arr[i][j] = inc++;
Well, first of all you have to fill the array with the numbers. You can use your double for loop for this and a counter variable which you increment after each loop of the inner for loop.
int counter = 1;
for(int x = 0; x < num1; x++)
{
for(int y = 0; y < num2; y++)
{
grid[x][y] = counter++;
}
}
Afterwards you can output the array again with a double for loop.
I am not sure if I understand you right.
You have problem with the code printing *?
If yes, then the reason for that is this
System.out.print("*");
Should be
System.out.print(grid[row]);
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Enter room length");
int arraySize = input.nextInt();
System.out.println("Length: " + (arraySize*arraySize));
int[][] array = new int[arraySize][arraySize];
int count = 1;
for (int i=0;i<arraySize;i++) {
for (int j=0;j<arraySize;j++) {
array[i][j] = count;
if (j != (arraySize-1))
System.out.print(count + "-");
else
System.out.println(count);
count++;
}
}
}
This code should print out the numbers how you want them.