Validating arrays

[ndolan33]

Alright so pretty much the program is supposed to have values entered in until the user inputs a "-1", then the program is supposed to stop asking. Also, no negative numbers below -1 are allowed but the code is supposed to keep asking until there is a positive number. I've done this before just never with an array. Any help is appreciated and I can post the assignment description if needed. I've been fooling around with it for a while but this is my original code i've been starting from scratch from.

#include <stdio.h>
#include <stdbool.h>

int getBoard ();
bool validate (int lengths[*]);

int main (void)
{
  getBoard ();
  return 0;
}

int getBoard ()
{
  int lengths[10]; //ARRAY FOR ALL THE TRIANGLES SIDE LENGTHS
  int n; //COUNTER FOR THE ARRAY
  bool valid; //TO CHECK TO SEE IF THE INPUT IS NOT NEGATIVE
  do
  {  
    for(n = 0; n < 10; n++)
    {
      printf("Enter the length of board #%d: ", (n + 1));
      scanf("%d", &lengths[n]);
    }
    valid = validate (lengths);
    if (!valid)
    {
      printf("Invalid negative input! Please try again!");
    }
  }while(!valid);
  return lengths[10];
}

bool validate (int lengths[10])
{
  bool valid = true; //BOOLEAN TO VALIDATE VALUES
  if (lengths[10] < -1)
  {  
    valid = false;
  }
  return valid;
}