how do I Convert a number into a BSTR? or just a string? (a BSRT is a visual basic string)

I need the C++ equivilent of
Code:
Dim str As String
Dim x As Double

x = 4

str = CStr(x)

I've tried VarBstrFromR8 API but it gives me the hexidecimal string, how do I get the actual string?