#define MAX 70000

function sqrt2_a( n as uinteger ) as uinteger
    return iif(n,2,1)
end function

function sqrt2_b( n as uinteger ) as uinteger
    return 1
end function

function napi_a( n as uinteger ) as uinteger
   return iif(n,n,2)
end function

function napi_b( n as uinteger ) as uinteger
   return iif(n>1,n-1,1)
end function

function pi_a( n as uinteger ) as uinteger
    return iif(n,6,3)
end function

function pi_b( n as uinteger ) as uinteger
    return (2*n-1)^2
end function

function calc_contfrac( an as function (as uinteger) as uinteger, bn as function (as uinteger) as uinteger, byval iter as uinteger ) as double
    dim as double r
    dim as integer i
    for i = iter to 1 step -1
        r = bn(i)/(an(i)+r)
    next i
    return an(0)+r
end function

print calc_contfrac( @sqrt2_a, @sqrt2_b, MAX )
print calc_contfrac( @napi_a, @napi_b, MAX )
print calc_contfrac( @pi_a, @pi_b, MAX )