如何在Swift 4中为Loop编写此代码

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

您可以这样写

SELECT RIGHT('0000' + CAST(CAST(FLOOR(RAND() * 10000) as int) as varchar(5)), 5)

  

需要IF语句，因为我们无法创建第一个元素低于最后一个元素的范围。