Pointers and Dynamically Allocated Arrays

[DawnDenise]

I see that this problem has been posted a few times before but I cannot manage to find the bug in my program. When it runs, it does not return the values in ascending order. For example, upon entering two test values, I get 0 and 1519848. Any hints would be greatly appreciated.

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

// Function prototypes
void arrSelectSort(int *[], int);
void showArrPtr(int *[], int);

int main()
{
   double *scores,         // To dynamically allocate an array
         total = 0.0,      // Accumulator
         average;          // To hold average scores
         
    int numScores,         //To hold the number of test scores
         count;            //Counter variable 

    // An array of pointers to int.
     int *arrPtr[numScores]; 
     
    // Each element of arrPtr is a pointer to int. Make each
    // element point to an element in the scores array.
            
        
    // Sort the elements of the array of pointers.
     arrSelectSort(arrPtr, numScores);    
   
    // Get the number of test scores
     cout << "How many test scores would you like to enter? ";
     cin >> numScores;

    // Dynamically allocate an array large enough to hold 
    // that many test scores
     scores = new double[numScores];

    // Get the test scores
     cout << "Enter the test scores below.\n";
     for (int count = 0; count < numScores; count++)
     {
          cout << "Score " << (count + 1) << ": ";
          cin >> scores[count];
          
          if (scores[count] < 0)
          {
          cout << " \nNegative test values are not possible.\n";
          cout << "Please run the program again and enter a positive integer.\n";
          while (scores[count] < 0);
          }
     }    

    // Calculate the total of the scores
      for (int count = 0; count < numScores; count++)
      {
          total += scores[count];
      }
          
    // Calculate the average score.
      average = total / numScores;           
        
    //  Display the results.
      cout << fixed << showpoint << setprecision(2);
      cout << "Average Score: " << average << endl;
      
    // Display the donations using the array of pointers. This
    // will display them in sorted order.
      cout << "The scores sorted in ascending order are: \n";   
      showArrPtr(arrPtr, numScores);
      
    // Free dynamically allocated memory
      delete [] scores;
      scores = 0;

cout << endl;      
system("PAUSE");
return 0;                       
}                                                            


void arrSelectSort(int *array[], int size)
{ 
    int startScan, minIndex;
    int *minElem;

    for (startScan = 0; startScan < (size - 1); startScan++)
    {
        minIndex = startScan;
        minElem = array[startScan];
        for (int index = startScan + 1; index < size; index++)
        {
            if (*(array[index]) < *minElem)
            {
                minElem = array[index];
                minIndex = index;
            }
        }
    array[minIndex] = array[startScan];
    array[startScan] = minElem;
    }
}

void showArrPtr(int *array[], int size)
{ 
    for (int count = 0; count < size; count++)
        cout << *(array[count]) << " ";
    cout << endl;
}

[cassandy]

i fixed your code, but i'll let you figure out what changed and why. you'll learn more that way. if you can't figure something out, ask and i'll tell you. :)

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

// Function prototypes
void arrSelectSort(double[], int);
void showArrPtr(double[], int);

int main()
{
    double *scores,         // To dynamically allocate an array
        total = 0.0,      // Accumulator
        average;          // To hold average scores
    int numScores;            //Counter variable    

    // Get the number of test scores
    cout << "How many test scores would you like to enter? ";
    cin >> numScores;

    // Dynamically allocate an array large enough to hold 
    // that many test scores
    scores = new double[numScores];

    // Get the test scores
    cout << "Enter the test scores below.\n";
    for (int count = 0; count < numScores; count++)
    {
        cout << "Score " << (count + 1) << ": ";
        cin >> scores[count];

        if (scores[count] < 0)
        {
            cout << " \nNegative test values are not possible.\n";
            cout << "Please run the program again and enter a positive integer.\n";
            while (scores[count] < 0);
        }
    }    

    // Calculate the total of the scores
    for (int count = 0; count < numScores; count++)
    {
        total += scores[count];
    }

    // Calculate the average score.
    average = total / numScores;           

    //  Display the results.
    cout << fixed << showpoint << setprecision(2);
    cout << "Average Score: " << average << endl;

    // Display the donations using the array of pointers. This
    // will display them in sorted order.
    cout << "The scores sorted in ascending order are: \n"; 
    arrSelectSort(scores, numScores); 
    showArrPtr(scores, numScores);

    // Free dynamically allocated memory
    delete [] scores;
    scores = 0;

    cout << endl;      
    system("PAUSE");
    return 0;                       
}                                                            


void arrSelectSort(double array[], int size)
{ 
    int startScan, minIndex;
    double minElem;

    for (startScan = 0; startScan < (size - 1); startScan++)
    {
        minIndex = startScan;
        minElem = array[startScan];
        for (int index = startScan + 1; index < size; index++)
        {
            if (array[index] < minElem)
            {
                minElem = array[index];
                minIndex = index;
            }
        }
        array[minIndex] = array[startScan];
        array[startScan] = minElem;
    }
}

void showArrPtr(double array[], int size)
{ 
    for (int count = 0; count < size; count++)
        cout << array[count] << " ";
    cout << endl;
}

[DawnDenise]

Thank you very much for your help.