Implementing merge sort in java 7 - java

I have a problem with implementation of merge sort in java. I am looking for the error almost week unfortunately without result. ArrayList at the entrance is the same as the output.
import java.util.ArrayList;
import java.util.Scanner;
public class MergeSort
{
private ArrayList<Integer> basicArrayList = new ArrayList<Integer>();
ArrayList<Integer> arrayListA = new ArrayList<Integer>();
ArrayList<Integer> arrayListB = new ArrayList<Integer>();
Scanner input = new Scanner(System.in);
private int firstIndexOfArrayList = 0;
private int lastIndexOfArrayListA;
private int lastIndexOfArrayListB;
public void Scal(ArrayList<Integer> basicArrayList, int p, int q, int r) {
this.firstIndexOfArrayList = p;
this.lastIndexOfArrayListA = q;
this.lastIndexOfArrayListB = r;
int numberOfElementsArrayListA = lastIndexOfArrayListA
- firstIndexOfArrayList + 1;
int numberOfElementsArrayListB = lastIndexOfArrayListB
- lastIndexOfArrayListA;
for (int i = 0; i < numberOfElementsArrayListA; i++) {
arrayListA.set(i, basicArrayList.get(firstIndexOfArrayList + i));
}
for (int j = 0; j < numberOfElementsArrayListB; j++) {
arrayListB.set(j, basicArrayList.get(lastIndexOfArrayListA + j));
}
arrayListA.add(Integer.MAX_VALUE);
arrayListB.add(Integer.MAX_VALUE);
int i = 0;
int j = 0;
for (int k = firstIndexOfArrayList; k <= lastIndexOfArrayListB; k++) {
if (arrayListA.get(i) <= arrayListB.get(j)) {
basicArrayList.set(k, arrayListA.get(i));
i = i + 1;
} else {
basicArrayList.set(k, arrayListB.get(j));
j = j + 1;
}
}
}
public void MergeSort(ArrayList basicArrayList, int p, int r) {
this.firstIndexOfArrayList = p;
this.lastIndexOfArrayListB = r;
if (firstIndexOfArrayList < lastIndexOfArrayListB) {
int lastIndexOfArrayListA = (firstIndexOfArrayList + lastIndexOfArrayListB) / 2;
MergeSort(basicArrayList, firstIndexOfArrayList,
lastIndexOfArrayListA);
MergeSort(basicArrayList, lastIndexOfArrayListA + 1,
lastIndexOfArrayListB);
Scal(basicArrayList, firstIndexOfArrayList,
lastIndexOfArrayListA,
lastIndexOfArrayListB);
}
}
public void setSize() {
System.out.println("Enter the number of elements to sort: ");
this.lastIndexOfArrayListB = input.nextInt();
}
public int getSize() {
return lastIndexOfArrayListB;
}
public void setData() {
System.out.println("Enter the numbers: ");
for (int i = 0; i < lastIndexOfArrayListB; i++) {
int number;
number = input.nextInt();
basicArrayList.add(number);
}
}
public void getTable() {
System.out.println(basicArrayList.toString());
}
public static void main(String[] args) {
MergeSort output = new MergeSort();
output.setSize();
output.setData();
output.MergeSort(output.basicArrayList,
output.firstIndexOfArrayList, (output.getSize() - 1));
output.getTable();
}
}

In terms of fixing your code I had a crack at it and as far as I can tell this seems to work. To do this a lot of your code had to be changed but it does now sort all Integers properly
import java.util.ArrayList;
import java.util.Scanner;
public class MergeSort
{
private ArrayList<Integer> basicArrayList = new ArrayList<Integer>();
Scanner input = new Scanner(System.in);
private int numbersToSort;
public void doMergeSort(int firstIndexOfArrayList,int lastIndexOfArrayListB, ArrayList<Integer> arrayList)
{
if(firstIndexOfArrayList<lastIndexOfArrayListB && (lastIndexOfArrayListB-firstIndexOfArrayList)>=1)
{
int mid = (lastIndexOfArrayListB + firstIndexOfArrayList)/2;
doMergeSort(firstIndexOfArrayList, mid, arrayList);
doMergeSort(mid+1, lastIndexOfArrayListB, arrayList);
Scal(firstIndexOfArrayList,mid,lastIndexOfArrayListB, arrayList);
}
}
public void Scal(int firstIndexOfArrayList,int lastIndexOfArrayListA,int lastIndexOfArrayListB, ArrayList<Integer> arrayList)
{
ArrayList<Integer> mergedSortedArray = new ArrayList<Integer>();
int leftIndex = firstIndexOfArrayList;
int rightIndex = lastIndexOfArrayListA+1;
while(leftIndex<=lastIndexOfArrayListA && rightIndex<=lastIndexOfArrayListB)
{
if(arrayList.get(leftIndex)<=arrayList.get(rightIndex))
{
mergedSortedArray.add(arrayList.get(leftIndex));
leftIndex++;
}
else
{
mergedSortedArray.add(arrayList.get(rightIndex));
rightIndex++;
}
}
while(leftIndex<=lastIndexOfArrayListA)
{
mergedSortedArray.add(arrayList.get(leftIndex));
leftIndex++;
}
while(rightIndex<=lastIndexOfArrayListB)
{
mergedSortedArray.add(arrayList.get(rightIndex));
rightIndex++;
}
int i = 0;
int j = firstIndexOfArrayList;
while(i<mergedSortedArray.size())
{
arrayList.set(j, mergedSortedArray.get(i++));
j++;
}
}
public void setSize()
{
System.out.println("Enter the number of elements to sort: ");
this.numbersToSort = input.nextInt();
}
public int getSize()
{
return numbersToSort;
}
public void setData()
{
System.out.println("Enter the numbers: ");
for (int i = 0; i < numbersToSort; i++)
{
int number;
number = input.nextInt();
basicArrayList.add(number);
}
}
public void getTable()
{
System.out.println(basicArrayList.toString());
}
public void runSort(ArrayList<Integer> arrayList)
{
doMergeSort(0, this.numbersToSort-1, arrayList);
}
public static void main(String[] args)
{
MergeSort output = new MergeSort();
output.setSize();
output.setData();
output.runSort(output.basicArrayList);
output.getTable();
}
}

Try this code. The following code takes an ArrayList input and outputs an ArrayList as well so it still works along the same basis of your code. The actual sort is handled in a different class MergeSort and is passes into ForMergeSort. Hope this helps
MergeSort.java
public class MergeSort
{
private int[] array;
private int[] tempMergArr;
private int length;
public void sort(int[] inputArr)
{
}
public int[] getSortedArray(int[] inputArr)
{
this.array = inputArr;
this.length = inputArr.length;
this.tempMergArr = new int[length];
doMergeSort(0, length - 1);
for(int i=0;i<length;i++)
{
int correctNumber = i+1;
System.out.println("Value "+correctNumber+" of the sorted array which was sorted via the Merge Sort is: "+inputArr[i]);
}
return inputArr;
}
private void doMergeSort(int lowerIndex, int higherIndex)
{
if (lowerIndex < higherIndex)
{
int middle = lowerIndex + (higherIndex - lowerIndex) / 2;
doMergeSort(lowerIndex, middle);
doMergeSort(middle + 1, higherIndex);
mergeParts(lowerIndex, middle, higherIndex);
}
}
private void mergeParts(int lowerIndex, int middle, int higherIndex)
{
for (int i = lowerIndex; i <= higherIndex; i++)
{
tempMergArr[i] = array[i];
}
int i = lowerIndex;
int j = middle + 1;
int k = lowerIndex;
while (i <= middle && j <= higherIndex)
{
if (tempMergArr[i] <= tempMergArr[j])
{
array[k] = tempMergArr[i];
i++;
}
else
{
array[k] = tempMergArr[j];
j++;
}
k++;
}
while (i <= middle)
{
array[k] = tempMergArr[i];
k++;
i++;
}
}
}
ForMergeSort.java
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
public class ForMergeSort
{
ArrayList<Integer> arrayList = new ArrayList<Integer>();
ArrayList<Integer> sortedArrayList = new ArrayList<Integer>();
MergeSort mS = new MergeSort();
public void buildArrayList()
{
Scanner input = new Scanner(System.in);
System.out.println("Enter the number of elements to sort: ");
int toSort = input.nextInt();
System.out.println("Enter the numbers: ");
for(int i =0; i<toSort; i++)
{
int number = input.nextInt();
arrayList.add(number);
}
}
public void runMergeSort(ArrayList<Integer> arrayList)
{
int[] arrayOfValues = new int[arrayList.size()];
int i = 0;
for(int a:arrayList)
{
arrayOfValues[i] = a;
i++;
}
MergeSort mS = new MergeSort();
for(int intOfArray:mS.getSortedArray(arrayOfValues))
{
sortedArrayList.add(intOfArray);
}
System.out.println(sortedArrayList.toString());
}
public static void main(String[] args)
{
ForMergeSort fMS = new ForMergeSort();
fMS.buildArrayList();
fMS.runMergeSort(fMS.arrayList);
}
}

Related

Why am I getting this IndexOutOfBoundsException error?

hi so im currently trying to get past this error in my code, if anyone could explain where I went wrong, would be greatly appreciated.
public class Lab07vst100SD
{
public static void main (String[] args)
{
System.out.println();
int size = 10;
School bhs = new School(size);
System.out.println(bhs);
System.out.println(bhs.linearSearch("Meg"));
System.out.println(bhs.linearSearch("Sid"));
System.out.println();
bhs.selectionSort();
System.out.println(bhs);
System.out.println(bhs.binarySearch("Meg"));
System.out.println(bhs.binarySearch("Sid"));
System.out.println();
}
}
class School
{
private ArrayList<Student> students;
private int size;
public School (int s)
{
students = new ArrayList<Student>();
size = s;
}
public void addData()
{
String [] name = {"Tom","Ann","Bob","Jan","Joe","Sue","Jay","Meg","Art","Deb"};
int[] age = {21,34,18,45,27,19,30,38,40,35};
double[] gpa = {1.685,3.875,2.5,4.0,2.975,3.225,3.65,2.0,3.999,2.125};
for(int i = 0; i < name.length; i++)
{
students.add(new Student(name[i], age[i], gpa[i]));
}
size = students.size();
}
public void selectionSort ()
{
for(int h = 0; h < students.size(); h++)
{
int index = h;
Student least = students.get(h);
for (int t = 0; t < size; t++) {
if (students.get(t).equals(least)) {
least = students.get(t);
index = t;
}
Student temp = students.get(h);
students.set(h, least);
students.set(t, temp);
}
}
}
public int linearSearch (String str)
{
// new arraylist
ArrayList<String> names = new ArrayList<String>();
for (int q = 0; q < size; q++) {
names.add(students.get(q).getName());
}
//comparison
for (int y = 0; y < size; y++) {
if (names.get(y).equals(str))
return y;
}
return -1;
};
public int binarySearch (String str) {
// new arraylist and variables
ArrayList<String> names = new ArrayList<String>();
Boolean found = false;
int lo = 0;
int hi = size;
int mid = (lo + hi) / 2;
//for loop for to transverse the array.
for (int m = 0; m < size; m++) {
names.add(students.get(m).getName());
}
while (lo <= hi && !found) {
if (names.get(mid).compareTo(str) == 0)
{
found = true;
return mid;
}
if (names.get(mid).compareTo(str) < 0) {
lo = mid + 1;
mid = (lo + hi) / 2;
}
else {
hi = mid -1;
mid = (lo + hi) / 2;
}
}
if (found)
return mid;
else
return -1;
}
public String toString() {
String temp = "";
for (int s = 0; s < students.size(); s++) {
temp += students.get(s);
}
return temp;
}
}
also, I should mention this uses the student class.
here
public class Student
{
private String name;
private int age;
private double gpa;
public Student (String n, int a, double g)
{
name = n;
age = a;
gpa = g;
}
public String getName() {
return name; }
public int getAge() {
return age; }
public double getGPA() {
return gpa; }
public String toString()
{
String temp = name + " " + age + " " + gpa + "\n";
return temp;
}
}
the school class calls to the student class.
this is what comes back.
Exception in thread "main" java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0
at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:64)
at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:70)
at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:248)
at java.base/java.util.Objects.checkIndex(Objects.java:359)
at java.base/java.util.ArrayList.get(ArrayList.java:427)
at School.linearSearch(Lab07vst100SD.java:78)
at Lab07vst100SD.main(Lab07vst100SD.java:16)
I'm completely confused on why this is happening, I think it may have to do with the ArrayList, other than that, I'm not sure.
please help, and thank you
p.s. I'm new so please bear with my horrible format.
You need call addData:
public static void main (String[] args)
{
System.out.println();
int size = 10;
School bhs = new School(size);
bhs.addData(); // here
System.out.println(bhs);
System.out.println(bhs.linearSearch("Meg"));
System.out.println(bhs.linearSearch("Sid"));
System.out.println();
bhs.selectionSort();
System.out.println(bhs);
System.out.println(bhs.binarySearch("Meg"));
System.out.println(bhs.binarySearch("Sid"));
System.out.println();
}
...
class School
{
private ArrayList<Student> students;
private int size;
public School (int s)
{
students = new ArrayList<Student>(); // Here, it can throw IndexOutOfBoundsException
size = s;
}
...
Please see https://www.tutorialspoint.com/java/util/arraylist_add_index.htm
The capacity of ArrayList must be initialized before ArrayList.add method
.

To find the single digit sum of palindrome numbers in array

I tried to check the palindrome number and find the single digit sum of the palindrome numbers, but my code is not returning the proper value (I am finding it difficult to return the value of sum from the loops). Can anyone help me getting the mistake. Any help will be appriciated.
import java.util.Scanner;
public class SumOfPalindrome {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of array elements");
int n = sc.nextInt();
int[] inp = new int[n];
System.out.println("enter the elements");
for(int i = 0; i< n ;i++)
{
inp[i] = sc.nextInt();
}
System.out.println(SumOfPalindromeNumber(inp));
}
private static int SumOfPalindromeNumber(int[] inp )
{
int sumpal =0;
for(int i = 0; i<inp.length;i++)
{
int rem =0;
int sum = 0;
while(inp[i]!=0)
{
rem = inp[i]%10;
sum=(sum*10)+rem;
inp[i]/=10;
}
if(inp[i]==sum)
{
sumpal+=inp[i];
if(sumpal>9)
{
sumpal=singledigitsum(sumpal);
}
}
}
return sumpal;
}
private static int singledigitsum(int sumpal)
{
int rem1 = 0;
int sum1 = 0;
while(sumpal!=0)
{
rem1=sumpal%10;
sum1+=rem1;
sumpal/=10;
}
if(sum1>9)
{
sum1=singledigitsum(sum1);
}
return sum1;
}
}
Enter numbers
Check which numbers are palindromes.
If that number is a palindrome then find sum of its digits.
Code:
import java.util.Scanner;
public class SumOfPalindrome {
public static void main(String[] args) {
SumOfPalindrome sumOfPalindrome=new SumOfPalindrome();
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of array elements");
int n = sc.nextInt();
int[] inp = new int[n];
System.out.println("enter the elements");
for(int i = 0; i< n ;i++)
{
inp[i] = sc.nextInt();
}
for(int i=0;i<n;i++)
{
if(sumOfPalindrome.isPallindrone(inp[i]))
{
System.out.println("No -> "+inp[i]+" Sum->"+sumOfPalindrome.sumOfDigits(inp[i]));
}
}
}//
public boolean isPallindrone(int no)
{
int r,sum=0,temp;
temp=no;
while(no>0){
r=no%10; //getting remainder
sum=(sum*10)+r;
no=no/10;
}
if(temp==sum)
{
return true;
}
else
{
return false;
}
}
public int sumOfDigits(int no)
{
int sum = 0;
while (no != 0)
{
sum = sum + no % 10;
no = no/10;
}
return sum;
}
}
I did not understand the purpose of sumpal in your code. You wanted a method which return sumOfPalindromes in an array. I commented the part which was wrong.
import java.util.Scanner;
public class SumOfPalindrome_1
{
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of array elements");
int n = sc.nextInt();
int[] inp = new int[n];
System.out.println("enter the elements");
for(int i = 0; i< n ;i++)
{
inp[i] = sc.nextInt();
}
//System.out.println(SumOfPalindromeNumber(inp));
SumOfPalindromeNumber(inp);
}
private static void SumOfPalindromeNumber(int[] inp )
{
int sumpal =0;
for(int i = 0; i<inp.length;i++)
{
int rem =0;
int sum = 0;
while(inp[i]!=0)
{
rem = inp[i]%10;
sum=(sum*10)+rem;
inp[i]/=10;
}
if(inp[i]==sum)
{
// sumpal+=inp[i];
/*if(sumpal>9)
{
sumpal=singledigitsum(sumpal);
}
*/
System.out.println(singleDigitSum(inp[i]));
}
}
}
private static int singleDigitSum(int sumpal)
{
int rem1 = 0;
int sum1 = 0;
while(sumpal!=0)
{
rem1=sumpal%10;
sum1+=rem1;
sumpal/=10;
}
if(sum1>9)
{
sum1=singleDigitSum(sum1);
}
return sum1;
}
}
Apologies if this is not the case but this seems like you are looking for answers to a coding test.

ACM-ICPC 7384 programming challenge

I'm trying to solve the Popular Vote problem, but I get runtime error and have no idea why, I really appreciate the help. Basically my solution is to get the total of votes, if all candidates have the same amount of votes; then there's no winner, otherwise I calculate the percentage of votes the winner gets in order to know if he's majority or minority winner.
import java.util.Scanner;
class popular {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
int n, suma, mayoria;
int casos=s.nextInt();
int cont=0;
int ganador=0;
float num=0;
while(cont!=casos){
n=s.nextInt();
int votos[]= new int[n];
for (int i = 0; i < n; i++) {
votos[i] = s.nextInt();
}
suma=sumar(votos);
if(suma==-1){
System.out.println("no winner");
}
else{
ganador=ganador(votos, suma);
num=(float)votos[ganador]/(float)suma;
if( num> 0.5){
System.out.println("majority winner "+(ganador+1));
}
else{
System.out.println("minority winner "+(ganador+1));
}
}
cont++;
ganador=0;
}
}
public static int sumar(int arreglo[]){
int resp1=-1, resp=0;
int temp=arreglo[0];
boolean sol=true;
for (int i = 0; i < arreglo.length; i++) {
resp=resp+arreglo[i];
if(temp!=arreglo[i]){
sol=false;
}
}
if(sol==false){
return resp;
}
return resp1;
}
public static int ganador(int arreglo[], int suma){
int mayor=0;
int ganador=0;
for (int i = 0; i < arreglo.length; i++) {
if(arreglo[i]>mayor){
mayor=arreglo[i];
ganador=i;
}
}
return ganador;
}
}
I submitted your code to the OJ, but I didn't get a runtime error, but I got Compilation error. I have to figure out there are some problems in your code. First of all, if you want to submit a java code to OJ, you need to name the public class as Main instead of popular or something else. Second, your code logic is not correct. Suppose a test case:
4
1
1
2
2
Your program will print "minority winner 3" but it's should be "no winner".
Here is a modified source code from yours (you can get accepted with this code):
import java.util.Scanner;
class Main {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
int n, suma, mayoria;
int casos = s.nextInt();
int cont = 0;
int ganador = 0;
float num = 0;
while (cont != casos) {
n = s.nextInt();
int votos[] = new int[n];
for (int i = 0; i < n; i++) {
votos[i] = s.nextInt();
}
ganador = findMaximum(votos);
if (getMaximumCount(votos, votos[ganador]) > 1) {
System.out.println("no winner");
} else {
suma = sumOf(votos);
if (votos[ganador] * 2 > suma) {
System.out.println("majority winner " + (ganador + 1));
} else {
System.out.println("minority winner " + (ganador + 1));
}
}
cont++;
ganador = 0;
}
}
private static int sumOf(int[] arreglo) {
int sum = 0;
for (int x : arreglo) {
sum += x;
}
return sum;
}
private static int getMaximumCount(int[] arreglo, int maximum) {
// Check if there are more than one items have the maximum value
int count = 0;
for (int x : arreglo) {
if (x == maximum) {
count++;
}
}
return count;
}
private static int findMaximum(int[] arreglo) {
int x = 0, pos = 0;
for (int i = 0; i < arreglo.length; i++) {
if (x < arreglo[i]) {
x = arreglo[i];
pos = i;
}
}
return pos;
}
}
Hope it could help you!

how to call a bubble sort in java

i need to do a bubble sort with 2 different set of datas. currently i have entered the bubble sort method twice so it can run with both set of data. is there a way to use a call method to the bubble sort.
int intJ1R1 = Integer.parseInt(txtJ1R1.getText());
int intJ2R1 = Integer.parseInt(txtJ2R1.getText());
int intJ3R1 = Integer.parseInt(txtJ3R1.getText());
int intJ4R1 = Integer.parseInt(txtJ4R1.getText());
int intJ5R1 = Integer.parseInt(txtJ5R1.getText());
int intJ6R1 = Integer.parseInt(txtJ6R1.getText());
double[] r1Array = {intJ1R1, intJ2R1, intJ3R1, intJ4R1, intJ5R1, intJ6R1};
double temp;
for (int i=0; i<r1Array.length; i++)
{
for (int j = 1; j <(r1Array.length-i); j++)
{
if (r1Array[j-1]>=r1Array[j])
{
temp=r1Array[j-1];
r1Array[j-1] = r1Array[j];
r1Array[j] = temp;
}
}
}
double totalR1 = (r1Array[1] + r1Array[2] + r1Array[3] + r1Array[4])/4;
String stringTotalR1 = Double.toString(totalR1);
lblTotalRun1.setText(stringTotalR1);
int intJ1R2 = Integer.parseInt(txtJ1R2.getText());
int intJ2R2 = Integer.parseInt(txtJ2R2.getText());
int intJ3R2 = Integer.parseInt(txtJ3R2.getText());
int intJ4R2 = Integer.parseInt(txtJ4R2.getText());
int intJ5R2 = Integer.parseInt(txtJ5R2.getText());
int intJ6R2 = Integer.parseInt(txtJ6R2.getText());
double[] r2Array = {intJ1R2, intJ2R2, intJ3R2, intJ4R2, intJ5R2, intJ6R2};
for (int i=0; i<r2Array.length; i++)
{
for (int j = 1; j <(r2Array.length-i); j++)
{
if (r2Array[j-1]>=r2Array[j])
{
temp=r2Array[j-1];
r2Array[j-1] = r2Array[j];
r2Array[j] = temp;
}
}
}
double totalR2 = (r2Array[1] + r2Array[2] + r2Array[3] + r2Array[4])/4;
String stringTotalR2 = Double.toString(totalR2);
lblTotalRun2.setText(stringTotalR2);
Create a method with the following signature:
public double[] bubbleSort(double[] array){
//move your sorting code here, and change array's name to array
return sortedArray;
}
Create a class and a method and then invoke the method from the main method
public class BubbleSort
{
public void bubbleSort(int value1, int value2, int value3, int value4, int value5, int value6) {
double[] r1Array = {value1, value2, value3, value4, value5, value6};
double temp;
for (int i=0; i<r1Array.length; i++)
{
for (int j = 1; j <(r1Array.length-i); j++)
{
if (r1Array[j-1]>=r1Array[j])
{
temp=r1Array[j-1];
r1Array[j-1] = r1Array[j];
r1Array[j] = temp;
}
}
}
double totalR1 = (r1Array[1] + r1Array[2] + r1Array[3] + r1Array[4])/4;
String stringTotalR1 = Double.toString(totalR1);
lblTotalRun1.setText(stringTotalR1);
}
public static void main(String[] args)
{
BubbleSort bubbleSort = new BubbleSort();
int intJ1R1 = Integer.parseInt(txtJ1R1.getText());
int intJ2R1 = Integer.parseInt(txtJ2R1.getText());
int intJ3R1 = Integer.parseInt(txtJ3R1.getText());
int intJ4R1 = Integer.parseInt(txtJ4R1.getText());
int intJ5R1 = Integer.parseInt(txtJ5R1.getText());
int intJ6R1 = Integer.parseInt(txtJ6R1.getText());
bubbleSort.bubbleSort(intJ1R1,intJ1R1,intJ1R1,intJ1R1,intJ1R1,intJ1R1);
int intJ1R2 = Integer.parseInt(txtJ1R2.getText());
int intJ2R2 = Integer.parseInt(txtJ2R2.getText());
int intJ3R2 = Integer.parseInt(txtJ3R2.getText());
int intJ4R2 = Integer.parseInt(txtJ4R2.getText());
int intJ5R2 = Integer.parseInt(txtJ5R2.getText());
int intJ6R2 = Integer.parseInt(txtJ6R2.getText());
bubbleSort.bubbleSort(intJ1R2,intJ1R2,intJ1R3,intJ1R4,intJ1R5,intJ1R6);
}
}
You can define the integer parameters inside the bubbleSort method itself once however since I don't know from What datatype you are converting to Integer hence have written it twice in main method itself
public static void main(String[] args)
{
BubbleSort bs = new BubbleSort(); //name of your class instead of BubbleSort
double[] r1Array = {intJ1R1, intJ2R1, intJ3R1, intJ4R1, intJ5R1, intJ6R1};
double[] r2Array = {intJ1R2, intJ2R2, intJ3R2, intJ4R2, intJ5R2, intJ6R2};
double[] sortedR1 = bs.bubbleSort(r1Array);
double[] sortedR2 = bs.bubbleSort(r2Array);
}
public double[] bubbleSort(double[] array){
double temp;
for (int i=0; i<array.length; i++)
{
for (int j = 1; j <(array.length-i); j++)
{
if (array[j-1]>=array[j])
{
temp=array[j-1];
array[j-1] = array[j];
array[j] = temp;
}
}
}
return array;
}

average method arrays hint

Can you give me a hint on what I'm doing wrong with my average in the average method? I'm trying to call the method in the read scores.I'm trying to get the average of the scores I have in my input.txt file.
import java.io.*;
import java.util.*;
public class FindGrade {
public static final int NUM_SCORE_TYPES = 5;
public static void main(String[] args) {
Scanner scan = null;
int[] quizArray = null;
int[] labArray = null;
int[] attendance = null;
int[] midterms = null;
int quizgrade =0;
int labgrade=0;
int attendance_1=0;
int midterms_1 =0;
String name;
try {
scan = new Scanner(new File("input.txt"));
} catch (FileNotFoundException e) {
e.printStackTrace();
return;
}
// each iteration is for single exam type (ie: Quizzes is the 1st one)
for (int i = 0; i < NUM_SCORE_TYPES; i++) {
name = scan.next();
int numScores = scan.nextInt();
int maxGrade = scan.nextInt();
if (name.equals("Quizzes")) {
quizArray = new int[numScores];
readScores(quizArray, numScores, scan);
}
else if (name.equals("Labs")) {
labArray = new int[numScores];
readScores(labArray, numScores, scan);
}
else if (name.equals("Lab_attendance")) {
attendance = new int[numScores];
readScores(attendance, numScores, scan);
}
else if (name.equals("Midterms")) {
midterms = new int[numScores];
readScores(midterms, numScores, scan);
}
}
}
public static void readScores(int[] scoreArray, int numScores, Scanner scan) {
for (int i = 0; i < numScores; i++) {
scoreArray[i] = scan.nextInt();
}
}
public static void average(double [] scoreArray, int numScores){
double sum=0;
for(int i=0; i< scoreArray.length; i++){
sum += scoreArray[i];
}
double average = sum/numScores;
System.out.println(sum + " " + average);
}
In any case, you can't directly call it with the arrays that you are creating there. Because the arrays are of type int, but the average-method requires a double array. When you change this, you can call the method like this...
public static void readScores(int[] scoreArray, int numScores, Scanner scan) {
for (int i = 0; i < numScores; i++) {
scoreArray[i] = scan.nextInt();
}
average(scoreArray, numScores); // <----- Call it here
}
public static void average(int[] scoreArray, int numScores){
double sum=0;
for(int i=0; i< scoreArray.length; i++){
sum += scoreArray[i];
}
double average = sum/numScores;
System.out.println(sum + " " + average);
}

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