void initArrays(float* x, float* y,int N){
  for(int i=0;i<N;i++){
    x[i] = 1;
    y[i] = 2;
  }
}

void addArrays(float*x,float* y,int N){
  for(int i=0;i<N;i++)
    y[i] = x[i] + y[i];
}

int main(void)
{
  int N = 1<<20;
  float *x, *y;

  x = (float*)malloc(N*sizeof(float));
  y = (float*)malloc(N*sizeof(float));
  initArrays(x,y,N);
  addArrays(x,y,N);

  free(x);
  free(y);

}