Re: [Dev-C++] Memory Error in simple array sort

[Per W. <pw...@ia...>]

How can you call fillArray and say that the size of the array is 10, when
I can clearly see that your array declaration is only of size 1...

/Per W

On Thu, 2 Oct 2003, Opacki, Joseph wrote:

> When I run the program below, I am getting a memory error:
>
> The instruction ...referenced memory...could not be "read".
>
> I don't exactly don't know what is going on hear, so I thoughI could reach
> out to the experts and ask.
>
> The program asks for a list of integers and inputs them into an array.  You
> end the list of integers with a negative number, then the app sorts it and
> redisplays your input to you lowest to greatest.  When ran I got the error
> above and it crashed.  I then put the sytem("pause") statement in and it ran
> fine.  After it paused, then it crashed.
>
> Here is the code:
>
> // array sort demonstration
> #include <iostream>
> #include <cstdlib>
>
> void fillArray(int a[], int size, int& numberUsed);
> /*
>     numberUsed is the number of values stored in a.  a[0] through
> a[numberUsed - 1]
>     have been filled with nonnegative integers read from the keyboard
> */
>
> void sort(int a[], int numberUsed);
> /*
>     the values of a[0] through a[numberUsed - 1] have been rearranged so
> that
>     a[0] <= a[1] <= a[2] ... a[numberUsed - 1]
> */
>
> void swapValues(int& v1, int& v2);
> // interchanges the values of v1 and v2
>
> int indexSmallest(const int a[], int startIndex, int numberUsed);
> /*
>     returns the index of i such that a[i] is the smallest of the values
>     a[startIndex, a[startIndex + 1] ..., a[numberUsed - 1]
> */
>
> int main()
> {
>     using namespace std;
>
>     cout << "This program sorts numbers from lowest to highest." << endl;
>
>     int sampleArray[1], numberUsed;
>
>     fillArray(sampleArray, 10, numberUsed);
>     sort(sampleArray, numberUsed);
>
>     cout << "In sorted order the numbers are: " << endl;
>
>     for ( int index = 0; index < numberUsed; index++ )
>     {
>         cout << sampleArray[index] << " ";
>     }
>
>     cout << endl;
>
>     system("PAUSE");
>     return 0;
> }
>
> void fillArray(int a[], int size, int& numberUsed)
> {
>     using namespace std;
>
>     cout << "Enter up to " << size << " nonnegative whole number.\n"
>          << "Mark the end of the list with a negative number.\n";
>
>     int next, index = 0;
>     cin >> next;
>
>     while ( (next >= 0) && (index < size) )
>     {
>         a[index] = next;
>         index++;
>         cin >> next;
>     }
>
>     numberUsed = index;
> }
>
> void sort(int a[], int numberUsed)
> {
>     int index_Smallest;
>
>     for ( int index = 0; index < numberUsed - 1; index++ )
>     { // place the correct value in a[index]
>         index_Smallest = indexSmallest(a, index, numberUsed);
>         swapValues(a[index], a[index_Smallest]);
>         // a[0] <= a[1] <= ... <= a[index] are the smallest of the original
> array
>         // elements.  The rest of the lements are in the remaining
> positions.
>     }
> }
>
> void swapValues(int& v1, int& v2)
> {
>     int temp;
>     temp = v1;
>     v1 = v2;
>     v2 = temp;
> }
>
> int indexSmallest(const int a[], int startIndex, int numberUsed)
> {
>     int min = a[startIndex], indexMin = startIndex;
>
>     for ( int index = startIndex + 1; index < numberUsed; index++ )
>     {
>         if ( a[index] < min ) // change to > to change sort arrangement
>         {
>             min = a[index];
>             indexMin = index;
>             // min is the smallest of a[startIndex] through a[index]
>         }
>     }
>
>     return indexMin;
> }
>
>
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