#include <stdio.h>
#include <stdint.h>

static uint16_t base[] = {1,2,3,4,5,6,7,8,9,10};
static uint16_t pattern[] = {4,5};

int8_t startIdx (uint16_t *table, uint8_t tblSize, uint16_t *match)
{
  for (int8_t idx =0; idx < tblSize-1; idx++)
    if (table[idx] == match[0] && table[idx+1] == match[1])
        return idx;
  return -1;
}

int main()
{
    printf("%d\n", startIdx(base, 10, pattern));
    return 0;
}