CODEWITHSUNDEEP
c++arrayssortingpointers
Mthagoura
Mthagoura

Reputation: 23

Pointer Based Bubble Sort in C++

Ive been trying to get the code to sort an user inputted array using a pointer based bubble sort in C++. The code compiles without error, but the array doesn't get sorted. Pointers have never been my strong area and I cant get them to work correctly. Heres my code.

#include <iostream>
using namespace std;

int main()
{
    int arr[10];
    int i = 0;
    for (i = 0; i < 10; i++)
    {
        cout << "Enter a number: ";
        cin >> arr[i];
    }

    int *ptr = &i;
    for (int j = 0; j < 9; j++)
    {
        if (*(ptr + j) > *(ptr + j + 1))
        {
            int temp = *(ptr + j);
            *(ptr + j) = *(ptr + j + 1);
            *(ptr + j + 1) = temp;
        }
    }

    cout << endl;
    for (i = 0; i < 10; i++)
        cout << arr[i] << "\t";

    cin.ignore();
    cin.get();
}

Thanks for the help guys.

Upvotes: 2

Views: 8713

Answers (1)

vsoftco
vsoftco

Reputation: 56557

You have 3 mistakes:

  1. As mentioned by @Lukasz P. in the comment, int* ptr should point to the array arr, int* ptr = arr;
  2. You access out of bounds for the last element (when j = 8)

  3. You need to keep sorting until there are no more swaps:

    bool sorted = false; // keep track here whether you still need to sort
int *ptr = arr;
while (!sorted) // repeat this until no more swaps
{
    sorted = true;
    for (int j = 0; j < 8 ; j++) // Repeat until N - 1 (i.e. 8 in this case)
    {
        if (*(ptr + j ) > *(ptr + j + 1)) // make sure you don't access out of bounds
        {
            int temp = *(ptr + j);
            *(ptr + j) = *(ptr + j + 1);
            *(ptr + j + 1) = temp;
            sorted = false; // we swapped, so keep sorting
        }
    }
}

Upvotes: 2

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