#include <stdio.h>

float
dotprod(int n, float x[], float y[]);

int main() {
    float a[3], b[3];
    float d;

    printf("Ax, Ay, Az: ");
    scanf("%f, %f, %f",
	  &a[0], &a[1], &a[2]);

    printf("Bx, By, Bz: ");
    scanf("%f, %f, %f",
	  &b[0], &b[1], &b[2]);

    d = dotprod(3, a, b);
    printf("Dot product: %f\n", d);
    return 0;
}