/*
 * Walk the moisture log with a pointer instead of an index.
 * README.md says how to build and run it.
 */
#include <stdio.h>

int sum_index(const int levels[], int count);
int sum_ptr(const int *levels, int count);
int find(const int *levels, int count, int target);

int main(void)
{
    int small[3] = {4, 5, 6};
    int levels[6] = {12, 3, 40, 7, 0, 100};
    int one[1] = {-9};

    /* The pointer walk must agree with the index walk. */
    if (sum_ptr(small, 3) == sum_index(small, 3)
            && sum_ptr(levels, 6) == sum_index(levels, 6)
            && sum_ptr(one, 1) == -9) {
        printf("check B1: PASS\n");
    } else {
        printf("check B1: FAIL, sum_ptr(levels) is %d but sum_index(levels) is %d\n",
               sum_ptr(levels, 6), sum_index(levels, 6));
    }

    if (find(levels, 6, 40) == 2 && find(levels, 6, 100) == 5) {
        printf("check B2: PASS\n");
    } else {
        printf("check B2: FAIL, find(levels, 6, 40) gave %d and find(levels, 6, 100) gave %d\n",
               find(levels, 6, 40), find(levels, 6, 100));
    }

    if (find(levels, 6, 55) == -1 && find(small, 0, 4) == -1) {
        printf("check B3: PASS\n");
    } else {
        printf("check B3: FAIL, a level that is not there should give -1\n");
    }

    printf("sum of levels: %d\n", sum_ptr(levels, 6));
    return 0;
}

/* Given: the index walk from Moisture Detection 2, to compare against. */
int sum_index(const int levels[], int count)
{
    int total = 0;
    int i;

    for (i = 0; i < count; i = i + 1) {
        total = total + levels[i];
    }
    return total;
}

/*
 * YOUR TASK: the same sum with no index and no [ ]. Start a pointer at levels
 * and move it one element at a time while it is before levels + count.
 */
int sum_ptr(const int *levels, int count)
{
    (void)levels; (void)count;                                 /* delete once you use them */
    return 0;
}

/*
 * YOUR TASK: walk a pointer through levels the same way. When it points at
 * target, return its index, worked out by subtracting two pointers. Return -1
 * when target is not there.
 */
int find(const int *levels, int count, int target)
{
    (void)levels; (void)count; (void)target;                   /* delete once you use them */
    return -1;
}