Resolved: function that returns a version of the given arrays where each zero value in the array is replaced by the smallest odd value to the right of 0. In C

#include <stdio.h></p>
<p>void lowestOdd(int num[], int size) {<br />
    int i, temp;<br />
    for (i = 0; i < size; i++) {
        if (num[i] % 2 != 0 && num[i] < num[i + 1]) {
            temp = num[i];
        }
    }

    for (i = 0; i < size; i++) {
        if (num[i] = 0) {
            num[i] = temp;
        }
    }
}

void printArray(int array[], int size) {
    int i;
    for (i = 0; i < size; i++) {
        printf("%d/n", array[i]);
    }
}

int main() {
    int i, size;
    int myarr[20];
    printf("What is the size of your array? \n");
    scanf("%d", &size);

    for (i = 0; i < size; i++) {
        scanf("%d", &myarr[i]);
    }
    lowestOdd(myarr[20], size);
    printArray(myarr[20], size);
    return 0;
}
[/code]

</p>



I've tried implementing pointers in the lowestOdd function, but to no avail. I do think they're necessary here, but I'm not really that good at pointers. The warnings I get are mostly 'warning: passing argument 1 of 'lowestOdd' makes pointer from integer without a cast [-Wint-conversion]'. Also, in my code, I haven't added the statements that would check whether the number is a zero or whether there are any odd values to the right of the zero.<br> 



<h2>Answer:</h2>



In the <a href="https://en.cppreference.com/w/c/language/declarations" rel="nofollow noreferrer">declaration</a><br> 


<p>[code]int myarr[20];

lowestOdd(myarr[20], size);

warning: passing argument 1 of 'lowestOdd' makes pointer from integer without a cast [-Wint-conversion]

if (num[i] % 2 != 0 && num[i] < num[i + 1])
[/code]

</p>



<code>num[i + 1]</code> will access <code>num[size]</code> when <code>i</code> is <code>size - 1</code> (again, valid indices are <code>0</code> to <code>size - 1</code>).<br> 



This is assignment<br> 


<p>[code]if (num[i] = 0)

if (num[i] == 0)

scanf("%d", &size);</p>
<p>for (i = 0; i < size; i++) {
    scanf("%d", &myarr[i]);
[/code]

</p>



risks the same out of bounds access if the user enters a value <em>greater</em> than <code>20</code> for <code>size</code>.<br> 



Ignoring the out of bounds access for a moment, <code>lowestOdd</code> attempts to find the last occurrence of the smaller number from each pair of numbers in the array, where the left number must be odd.<br> 



It then replaces all zeroes in the array with this value.<br> 



There is a chance <code>temp</code> is never assigned anything, and thus has an indeterminate value.<br> 



This is not correct.<br> 



Here is an example program (using a <a href="https://en.cppreference.com/w/c/language/array#Variable-length_arrays" rel="nofollow noreferrer">variable-length array</a>).<br> 



Note that the syntax <code>array + i</code> is equivalent to <code>&array[i]</code>.<br> 



<code>? :</code> is the <a href="https://en.cppreference.com/w/c/language/operator_other#Conditional_operator" rel="nofollow noreferrer">conditional operator</a>: in <code>a ? b : c</code>, if <code>a</code> is non-zero the expression evaluates to <code>b</code>, else it evaluates to <code>c</code>.<br> 


<p>[code]#include <stdio.h></p>
<p>int min(int a, int b)<br />
{<br />
    return a < b ? a : b;
}

int find_lowest_odd(int *base, size_t len)
{
    int value = 0;

    for (size_t i = 0; i < len; i++)
        if (base[i] & 1) /* base[i] % 2 != 0 */
            value = value ? min(value, base[i]) : base[i];

    return value;
}

void mutate_array(int *a, size_t len)
{
    for (size_t i = 0; i < len; i++)
        if (0 == a[i])            /* search from the next position */
            a[i] = find_lowest_odd(a + i + 1, len - i - 1);
}

void print_array(int *a, size_t len)
{
    for (size_t i = 0; i < len; i++)
        printf("%d ", a[i]);

    putchar('\n');
}

int main(void) {
    size_t size;

    printf("What is the size of your array?: ");

    if (1 != scanf("%zu", &size))
        return 1;

    int array[size];

    for (size_t i = 0; i < size; i++) {
        printf("#%zu: ", i + 1);

        if (1 != scanf("%d", array + i))
            return 1;
    }

    print_array(array, size);
    mutate_array(array, size);
    print_array(array, size);
}
[/code]

</p>



I/O:<br> 


<p>[code]What is the size of your array?: 10<br />
#1: 0<br />
#2: 2<br />
#3: 0<br />
#4: 5<br />
#5: 3<br />
#6: 0<br />
#7: 7<br />
#8: 2<br />
#9: 0<br />
#10: 0<br />
0 2 0 5 3 0 7 2 0 0<br />
3 2 3 5 3 7 7 2 0 0