#include <stdio.h>
int max(int arr[], int length)
{
if (length <= 0) return -1;
int max = arr[0];
int i = 0;
for (; i<length; i++)
max = max < arr[i] ? arr[i] : max;
return max;
}
int main()
{
int arr0[5] = {1,5, 4, 4, 2};
printf("max : %d\n", max(arr0, 5));
int arr1[5] = {1, 2, 3, 4, 5};
printf("max : %d\n", max(arr1, -1));
int arr2[] = {};
printf("max : %d\n", max(arr2, 0));
return 0;
}