Answer:
Answered in C++
#include <iostream>
using namespace std;
int main() {
    int size;
    cout<<"Length of array: ";
    cin >> size;
    double *numDoubles = new double[size];
    double sum =0;
    cout<<"Array Elements: ";
    for(int i=0;i<size;i++){
        cin>>numDoubles[i];
        sum += numDoubles[i];
    }
    delete [] numDoubles;
    cout<<"Average: "<<sum/size;
    return 0;  
}
Explanation:
This line declares the size (or length) of the array
<em>    int size;
</em>
This line prompts the user for the array length
<em>    cout<<"Length of array: ";
</em>
This gets the input from the user
<em>    cin >> size;
</em>
This dynamically declares the array as of double datatype
<em>    double *numDoubles = new double[size];
</em>
This declares and initializes sum to 0
<em>    double sum =0;
</em>
This prompts the user for elements of the array
<em>    cout<<"Array Elements: ";
</em>
The following iteration gets input from the user and also calculates the sum of the array elements
<em>    for(int i=0;i<size;i++){
</em>
<em>        cin>>numDoubles[i];
</em>
<em>        sum += numDoubles[i];
</em>
<em>    }
</em>
This deletes the array
<em>    delete [] myarray;
</em>
This calculates and prints the average of the array
<em>    cout<<"Average: "<<sum/size;
</em>