Question

Write a function that removes all even numbers from an array. The function should take the array, length of the array, and a pointer for number of odd numbers found as arguments and return a pointer to the new array. If there are no odd numbers found in the array, your code should print "No odds found." and return NULL.

Use the function header:

int *removeEvens(int *a, int length, int *oddsFound);

Example:

Input array a[ ] = {3, 4, 5, 6, 7}

*oddsFound = 3

return array = {3, 5, 7}

The size of the return array needs to be the number of odd numbers found.

Note: You can determine if a number is even by checking if a[x] % 2 == 0.

Answer 1

C++ Program:

#include <iostream>

using namespace std;

//Function that removes even numbers from array
int *removeEvens(int *a, int length, int *oddsFound)
{
    int i, k=0;

    int *oddNumbers;

    //Initializing oddsFound to 0
    *oddsFound = 0;

    //Counting number of odd numbers
    for(i=0; i<length; i++)
    {
        //Evaluating for odd number
        if(a[i] % 2 != 0)
            //Incrementing count
            *oddsFound += 1;
    }

    //If there are no odd numbers
    if(oddNumbers == 0)
    {
        //Printing error message and returns NULL
        cout << "\n\n No odds found. \n\n";
        return NULL;
    }
    else
    {
        //Allocating space to array
        oddNumbers = new int[*oddsFound];

        //Storing odd numbers
        for(i=0; i<length; i++)
        {
            //Searching for odd number
            if(a[i] % 2 != 0)
            {
                //Adding to array
                oddNumbers[k] = a[i];
                k++;
            }
        }

        //Returns odd numbers array
        return oddNumbers;
    }
}

//Main function
int main()
{
    //Array
    int a[] = {3, 4, 5, 6, 7};
    int oddsFound;
    int *oddNumbers;
    int i;

    //Calling function
    oddNumbers = removeEvens(a, 5, &oddsFound);

    cout << "\n\n Odd numbers: ";

    //Printing odd numbers
    for(i=0; i<oddsFound; i++)
    {
        cout << " " << oddNumbers[i];
    }

    cout << "\n\n";
    return 0;
}

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Sample Output: