Write Julia functions to convert decimal numbers—both integer or fractional—into their binary representation.

This is working to about 64 bits.

# converts the fractional part of a decimal number (i.e., less than 1)
# into its binary form. Number must be <1 and >2^-64.

function fracdec2bin(n)
    nbits = 64;
    global b=zeros(Int,nbits);
    k=0;
    while n != 2.0^-k && k < nbits
        k+=1;
        if n-2.0^-k > 0
            n=n-2.0^-k
            b[k]=1
        end
    end
    if n == 2.0^-k
        b[k]=1
    end
    "0."*join(string.(b))
end

function intdec2bin(n)
    nbits = 63;
    global b=zeros(Int,nbits);
    global k=nbits;
    while n != 2^k && k > 0
        if n-2^k >= 0
            n=n-2^k
            b[nbits-k]=1
        end
        k-=1;
    end
    if n == 2^k
        b[nbits-k]=1
    elseif k == 1
        b[nbits]=1
    end
    join(string.(b))
end