Returning results from a function using pointers

Hello all, I am needing to calculate the amounts of the values stored in the arrays within a function. The calculations within the function however have to be done using pointers. I am having trouble figuring out how to return the value calculated and display it within main. This is what I have so far, any help would be great.

Code:

`#include <stdio.h>`

double extend (double [], double [], double []);

int main ()

{

#define max 10

double price [max] = {10.62, 14.89, 13.21, 16.55, 19.62, 9.47, 6.58, 19.32, 12.15, 3.99};

double quantity [max] = {4, 9.5,6, 7.35, 9, 15.3, 3, 5.4, 2.9, 4.9};

double amount [max];

int i;

for (i=0; i<max; i++){

printf ("The amount is %f\n", extend(price, quantity, amount));

}

system ("PAUSE");

return 0;

}

double extend (double price[], double quantity[], double amount [])

{

int i;

double *gPtr, *mPtr, *nPtr;

gPtr= price;

mPtr= quantity;

nPtr= amount;

for (i=0; i<max; i++){

*nPtr++= *mPtr++ * *gPtr++;

}

return (amount);

}