Convert.ToString() to binary format not working as expected

Question

int i = 20;
string output = Convert.ToString(i, 2); // Base2 formatting
i = -20;
output = Convert.ToString(i, 2);

Value   Expected                       


        

Answer 1

Negative numbers in .NET are represented in binary as Two's complement.

From MSDN - Convert.ToString Method (Int32, Int32):

If value is negative and toBase is 2, 8, or 16, the returned string uses two's complement representation