复利计算

func computer(principal: Double, rate: Double, add: Double, years: Int) {
    var amount = principal
    for _ in 1...years {
        amount = amount * rate + add
    }
    if amount > 10000 && amount < 100000000 {
        print("\(years)年：\(String(format: "%.2f", amount/10000.0))万")
    }
    if amount > 100000000 {
        print("\(years)年：\(String(format: "%.2f", amount/100000000.0))亿")
    }
}

let princiap:Double = 10000
let rate:Double = 1.2
let add:Double = 10000
computer(principal: princiap, rate: rate, add: add, years: 3)
computer(principal: princiap, rate: rate, add: add, years: 5)
computer(principal: princiap, rate: rate, add: add, years: 10)
computer(principal: princiap, rate: rate, add: add, years: 15)
computer(principal: princiap, rate: rate, add: add, years: 20)
computer(principal: princiap, rate: rate, add: add, years: 25)
computer(principal: princiap, rate: rate, add: add, years: 30)
computer(principal: princiap, rate: rate, add: add, years: 60)