#define NAN 0.0/0.0  'dot product of different-dimensioned vectors is no more defined than 0/0

function dot( a() as double, b() as double ) as double
    if ubound(a)<>ubound(b) then return NAN
    dim as uinteger i
    dim as double dp = 0.0
    for i = 0 to ubound(a)
        dp += a(i)*b(i)
    next i
    return dp
end function

dim as double zero3d(0 to 2) = {0.0, 0.0, 0.0}     'some example vectors
dim as double zero5d(0 to 4) = {0.0, 0.0, 0.0, 0.0, 0.0}
dim as double x(0 to 2) = {1.0, 0.0, 0.0}
dim as double y(0 to 2) = {0.0, 1.0, 0.0}
dim as double z(0 to 2) = {0.0, 0.0, 1.0}
dim as double q(0 to 2) = {1.0, 1.0, 3.14159}
dim as double r(0 to 2) = {-1.0, 2.618033989, 3.0}

print " q dot r           = ", dot(q(), r())
print " zero3d dot zero5d = ", dot(zero3d(), zero5d())
print " zero3d dot x      = ", dot(zero3d(), x())
print " z dot z           = ", dot(z(), z())
print " y dot z           = ", dot(y(), z())