为什么以下给我零?

Why is the following giving me zero?

下面的每个打印语句都会产生 0.0

var c:Double = 0.0
let a:Int = 1
let b:Int = 5
print("a/b = \(Double(a/b * 100))")
c = Double(a/b * 100)
print("c = \(c)")

这是因为整数除法。将 Double(a/b * 100) 更改为 Double(a) / Double(b) * 100