I'm having trouble figuring out why my Merge Sort function won't work. Any help would greatly be appreciated.

#include

#include

#include

using namespace std;

// Utility function

void printArray(int array[], int length) {

for (int i = 0; i < length; i++) {

cout << array[i] << " ";

}

cout << " ";

}

void merge(int arr[], int start, int middle, int end) {

int i = 0;

int j = 0;

int k = start;

// Create two lists to store the halved array.

int list1 = (middle - start) + 1;

int list2 = (end - middle);

// We use a vector here because the list sizes aren't known until runtime.

// Therefore, an array declaration won't work here.

vector left(list1), right(list2);

for (int i = 0; i < list1; i++) {

left[i] = arr[start + i];

}

for (int j = 0; j < list2; j++) {

right[j] = arr[middle + 1 + j];

}

// Continue sorting while there are elements that need to be sorted.

while (i < list1 && j < list2){

// If the head of the first list is smaller than or equal to the head of the right:

if (left[i] <= right[j]){

// Place the smaller element first.

arr[k] = left[i];

i++;

}

// Else the head of the second list is smaller,

else {

// So place that element first instead.

arr[k] = right[j];

j++;

}

k++;

}

while (i < list1) {

arr[k] = left[i];

i++;

k++;

}

while (j < list2) {

arr[k] = right[j];

j++;

k++;

}

}

// Recursive Merge Sort Implementation

void mergeSort(int array[], int start, int end)

{

// Base case

if (start >= end) {

return;

}

// Step 1: Divide the array in half to find the middle index.

int middle = start + (end - start) / 2;

// Create temporary arrays for the left and the right.

// Step 2: Recursively sort each half.

// Recursive call on the first half.

mergeSort(array, start, middle);

// Recursive call on the second half.

mergeSort(array, middle + 1, end);

//Step 3: Call the merge subroutine.

merge(array, start, middle, end);

}

int main() {

//int array[10] = { 2,5,6,4,7,2,8,3,9,10 };

//int iArray[] = { 4, 19, 2, 5, 11 };

//int numElements = sizeof(array) / sizeof(array[0]);

//cout << "Number of elements in the array: " << numElements << endl;

//cout << "Array to be sorted: " << endl;

//printArray(array, numElements);

//cout << "Array after being sorted: " << endl;

////mergeSort(array, 0, 9);

//mergeSort(array, 0, numElements - 1);

////Print the sorted array

////printArray(array, 10);

//printArray(array, numElements);

cout << "Merge Sort Implementation" << endl;

ifstream in("data.txt");

if (in.fail()) {

cout << "ERROR: Unable to open file." << endl;

return 0;

}

ofstream out("results.txt");

int n;

// reading size

while (in >> n) {

// Create an array based on length.

int *array = new int[n];

// Read each element.

int j = 0;

while (j < n) {

in >> array[j];

j++;

}

cout << "Number of elements to be sorted: " << n;

cout << endl;

cout << "Array to be sorted: ";

printArray(array, n);

cout << endl;

// Call Merge Sort procedure.

mergeSort(array, j, n);

//mergeSort(array, 0, n);

// Write the results to the file.

for (int i = 0; i < n; i++) {

out << array[i] << " ";

}

out << endl;

printArray(array, n);

cout << endl;

}

in.close();

out.close();

cout << "Sorted results written to 'results.txt'" << endl;

return 0;

}