C++ Array to a number

Question

I have no idea how to write a code which would take numbers from the array and equal them to an integer number without 0.

For example, I have an array A[size]= {12,68,45,20,10} and I need to get the answer as n= 12684521. Any ideas or hints how to make it?

Answer 1

It is possible to do it without using strings or stringstreams. Here's the code:

int integer(int* arr, size_t length)
{
    int result = 0;
    for (size_t i = 0; i < length; i++)
    {
        int t1 = arr[i], t2 = 0;
        while (t1 != 0)
        {
            if(t1 % 10 != 0)
            {
                t2 *= 10;
                t2 += t1 % 10;
            }
            t1 /= 10;
        }
        while (t2 != 0)
        {
            if(t2 % 10 != 0)
            {
                result *= 10;
                result += t2 % 10;
            }
            t2 /= 10;
        }
    }
    return result;
}

The quirky thing is to make two inner while loops because operations in one of those loops mirror the numbers (e.g. if arr[i] is 68 then t2 becomes 86 and then 6 and 8 are appended to result).