How to write this for Loop in swift 4

Question

for var i=count-2; i>=0; --i
{
     if let nextControlPoint = firstControlPoints[i+1]
    {

        let controlPointX = (rhsArray[i].x.f - c[i] * nextControlPoint.x.f)/b[i]
        let controlPointY = (rhsArray[i].y.f - c[i] * nextControlPoint.y.f)/b[i]

    }

    z += 1

}

Answer 1

You can write something like this

if count > 1 {
    for i in (0...count-2).reversed() {
        print(i)
    }
}

The IF statement is needed because we cannot create a range where the first element is lower than the last one.