Bandpass filter

I have error A and warrning B

A. error: #137: expression must be a modifiable lvalue

" next output value = yv16];" - what I should put in this line ?
I put 1
1 = yv[16]; _ I have error A

B, warning: #177-D: function "filterloop" was declared but never referenced

/* Infinite loop /
/
USER CODE BEGIN WHILE /
while (1)
{
/
USER CODE END WHILE */

/* USER CODE BEGIN 3 */

}
/* USER CODE END 3 */

What I should put for loop code ?