#include <cstdlib>
#include <iostream>
#include <iomanip>
using namespace std;

bool isSorted(int* ar, int len);
void initArray(int* ar, int len);
void displayArray(int* ar, int len);
void swap(int* ar, int pos1, int pos2);

int main(int argc, char** argv) {
    srand(time(NULL));          // initialize random number generator
    const int NUM_TESTS = 1703; // number of tests to run on sort
    int errorCount = 0;         // keeps track of how many tests fail
    int arraySize = 0;          // keeps track of length of array
    int* nums = NULL;           // pointer to array
    int sum = 0;                // used to make sure array has not been corrupted

    // Run the code for the number of tests specified
    for (int test = 1; test <= NUM_TESTS; test++) {
        // Display the test number every 100 tests and at end
        if (test % 100 == 0 || test == NUM_TESTS) {
            cout << "\rTest number " << test;
            cout.flush();
        }

        // Create an array of random size from 1 - 1000
        arraySize = rand() % 1000 + 1;
        nums = new int[arraySize];
        if (nums == NULL) {
            cout << "Error allocating space for array\n";
            exit(EXIT_FAILURE);
        }

        // Fill array with random numbers
        initArray(nums, arraySize);
        // Get sum for array to check if it is same after sorting
        sum = sumArray(nums, arraySize);
        // Sort array
        sort(nums, arraySize);
        
        // Make sure array is sorted and sum is consistent
        if (sum != sumArray(nums, arraySize)) {
            cout << "Error: Array corrupted.\n";
            errorCount++;
        } else if (!isSorted(nums, arraySize)) {
            cout << "Error: Array not sorted\n";
            errorCount++;
        }
        
        // Free memory used by array
        delete[] nums;
    }
    
    cout << "\nNumber of tests: " << NUM_TESTS << '\n'; 
    cout << "Number of errors: " << errorCount << '\n'; 
    
    return 0;
}

/*
    Name: isSorted
    Input:
        ar: a pointer to an array of integers
        len: the length of the array
    Output:
        true if the array is sorted, otherwise false
*/
bool isSorted(int* ar, int len) {
    bool sorted = true;
    for (int i=0; i<len-1; i++) {
        if (*(ar+i) > *(ar+i+1)) {
            sorted = false;
            break;
        }
    }
    return sorted;
}

/*
    Name: initArray
    Input:
        ar: a pointer to an array of integers
        len: the length of the array
    Output:
        None
    Side effect:
        The input array is sorted in ascending order.
*/
void initArray(int* ar, int len) {
    for (int i=0; i<len; i++) {
        *(ar+i) = rand() % 1000 + 1;
    }
}

/*
    Name: displayArray
    Input:
        ar: a pointer to an array of integers
        len: the length of the array
    Output:
        None
    Side effect:
        The input array is displayed on the screen in ten columns of width five.
        A newline is displayed after every tenth item and after the last item.
*/
void displayArray(int* ar, int len) {
    for (int i=0; i<len; i++) {
        cout << setw(5) << *(ar+i);
        if (i == len-1 || i % 10 == 9) cout << '\n';
    }
}

/*
    Name: swap
    Input:
        ar: a pointer to an array of integers
        pos1: an index of one item in the array to be swapped
        pos2: an index of another item in the array to be swapped
    Output:
        None
    Side effect:
        The two items in the input array are swapped.
*/
void swap(int* ar, int pos1, int pos2) {
    // Only swap if the two items are not the same item
    if (pos1 != pos2) {
        int temp = *(ar+pos1);
        *(ar+pos1) = *(ar+pos2);
        *(ar+pos2) = temp;
    }
}