How to get whether there are elements left in array or not

Question

int main()
{
    int arr[10000] = {1, 2, 3, 4};
    int i = 0;
    int num = 0;
    int n = 10;
    
    while(arr[i] != null){
        num = num * n + arr[i];
        i++;
    }
    
    cout << num << '\n';
    
    return 0;
}

It throws error, but i don't know how to get if there're left any elements in my array or not, but i don't want to change null with 0, because it is possible certain element to be 0.

Answer 1

You can initialize your array with a number that you're not going to use. Suppose you do it with -1 or you can even take INT_MAX (max value 32-bit integer can store).
But keep in mind that in order to use INT_MAX you'll need to include the header: #include<limits.h>

Now you need to initialize the array either by simply running a loop over the size of the array or by using the memset function.

Now you can use while(arr[i] != -1) or while(arr[i] != INT_MAX). The loop will stop after your elements are done processing. That way you'll know if there are elements left in your array. Hope this helps.