nanodbc get SQL type FLOAT as C++ std::string truncates characters

Question

I'm using the nanodbc ODBC C++ library

to retrieve a row of data from a table that has a SQL FLOAT type in a column, that for that record was saved to the database as "1.4" the following program returns that value as std::string = "1"

how can I get the string as the value that was saved , "1.4" ?

    #include <iostream>
#include <nanodbc/nanodbc.h>

using namespace std;
using namespace nanodbc;

void show(nanodbc::result& results);

int main(int, char*[])
{
    try
    {
        auto const connection_string =
            NANODBC_TEXT("Driver={SQL Server};Server=localhost;Database=test_db;");
        connection conn(connection_string);
        std::cout << conn.dbms_name() << std::endl;

        execute(conn, "drop table if exists test_table;");
        execute(conn, "create table test_table (a float, b varchar(10));");
        execute(conn, "insert into test_table VALUES (1.4, 'foo');");
        result result = execute(conn, NANODBC_TEXT("SELECT TOP 1 * FROM [test_table];"));
        show(result);
    }
    catch (std::runtime_error const& e)
    {
        std::cerr << e.what() << std::endl;
    }
}

void show(nanodbc::result& results)
{
    const short columns = results.columns();

    nanodbc::string const null_value = NANODBC_TEXT("NULL");
    while (results.next())
    {
        for (short col = 0; col < columns; ++col)
        {
            cout << results.column_name(col) << " : ";
            std::string value = results.get<nanodbc::string>(col, null_value);
            cout << value << "\n";
        }
        cout << endl;
    }
}

output

Microsoft SQL Server
a : 1
b : foo