#include <stdio.h>

int numOfRecursiveCalls;

void calculatePolynomial(double*, double*, int, double, double);

int main() {
    int n;

    double x0;
    double result = 0.0;

    printf("Enter n: ");
    scanf("%d", &n);

    if(n < 0) {
        printf("\nThe power must be greater or equal to 0.");
        return 1;
    }

    n++;

    printf("\nEnter x0: ");
    scanf("%lf", &x0);

    printf("\n");

    double* a = (double*) malloc(n * sizeof(double));

    for(int i = 0; i < n; i++) {
        printf("Enter a[%d] element: ", i);
        scanf("%lf", a + i);
    }

    calculatePolynomial(&result, a, n - 1, 1, x0);

    printf("\nResult: %.2lf\nNumber of recursive calls: %d\n", result, numOfRecursiveCalls);


    free(a);

    return 0;
}

void calculatePolynomial(double* result, double* a, int i, double multiplier, double x0) {
    if(i < 0) {
        return;
    }

    numOfRecursiveCalls++;

    *result = *result + a[i] * multiplier;

    return calculatePolynomial(result, a, --i, multiplier * x0, x0);
}