Cannot implicitly convert type 'System.Numerics.BigInteger' to 'int'. An explicit conversion exists (are you missing a cast?)

Question

I have an array and simple loop:

static BigInteger[] dataSet = new BigInteger[] { 100913, 1009139, 10091401, 100914061, 1009140611, 10091406133, 100914061337, 1009140613399 };


 foreach (BigInteger num in dataSet ) {

                BigInteger[] Vector = new BigInteger[num];

                for (BigInteger i = 1; i <= num; i++)  {
                    Vector[i - 1] = i;
                }
            }

Can anyone explain why this code returns

Cannot implicitly convert type 'System.Numerics.BigInteger' to 'int'. An explicit conversion exists (are you missing a cast?)

Error appears in this line:

BigInteger[] Vector = new BigInteger[num]; 

Everything is converted to BigInteger, I do not see the possible reasons.

Will be thankful for help,

Thanks in advance,

Answer 1

num is a BigInteger but you are using it to initialise the size of your array:

BigInteger[] Vector = new BigInteger[num];

The indexer of an array is int, meaning that largest size you can create is int.MaxValue (2,147,483,647).