#include <stdio.h>

float scalarproduct(int n, float *x, float *y)
{
  float scalar;
  int i;

  for (i = 0; i < n; i++)
    scalar += (x[i] * y[i]);

  //printf("Scalar product is: %f\n",scalar);

  return scalar;
}

int main()
{
  float x[4] = {1.0,2.0,3.0,4.0};
  float y[4] = {4.0,3.0,2.0,1.0};
  float scalar;
  scalar = scalarproduct(4, x, y);
  printf("Scalar product is: %f\n", scalar);
}