Question

我最近开始学习C ++和Swift。我已经用C ++编写了一些程序，并决定尝试将其中一个程序翻译成Swift。我遇到了一个问题。当我尝试使用readline()从Swift中的用户获取输入时，它将数字保存为字符串而不是Double。因此，每当我尝试计算时，我的程序中都会出现错误。

二进制运算符'*'不能应用于'Double'和'String'
类型的操作数

我已经尝试在互联网上搜索纠正此问题的方法，但我发现的所有说明都已过时。如果有人能提供帮助，我们将不胜感激。

以下是我尝试将C ++代码翻译成Swift。

/* Calculate and display the circumference of a circular gazebo and the price of the railing materials for it. */

import Foundation

//Declare Name Constants
let PI : Double = 3.141593

//Input
print("Enter the diameter (in feet) of the gazebo: ")
let gazeboDiameter = (readLine()!)

print ("Enter the price (per foot) of railing material: ")
let priceOfRailing = ((readLine()!)

// Calculate circumference and price
let circumference = PI * gazeboDiameter
let costOfGazebo = circumference * priceOfRailing

//Output
print("The Diameter of the Gazebo is: " (gazeboDiameter))
print("The price (per foot) of the railing material is: "(costOfGazebo))
print("The circumference of the gazebo is: " (circumference))
print("The price of the railing will be: $"(costOfGazebo))

Answer 1

readLine（strippingNewline :)返回String类型的对象。因此，您必须尝试从String转换为double。然后你的程序变成：

//SWIFT
/* Calculate and display the circumference of a circular gazebo and the price of the railing materials for it. */

import Foundation

//Declare Variables
var gazeboDiameter: Double = 0.0
var priceOfRailing: Double = 0.0
var circumference: Double = 0.0
var costOfGazebo: Double = 0.0

//Input
print("Enter the diameter (in feet) of the gazebo: ")
gazeboDiameter = Double(readLine()!)!

print ("Enter the price (per foot) of railing material: ")
priceOfRailing = Double(readLine()!)!

// Calculate circumference and price
circumference = Double.pi * gazeboDiameter
costOfGazebo = circumference * priceOfRailing

//Output
print("The Diameter of the Gazebo is: \(gazeboDiameter)")
print("The price (per foot) of the railing material is: \(costOfGazebo)")
print("The circumference of the gazebo is: \(circumference)")
print("The price of the railing will be: $\(costOfGazebo)")

需要一种方法供用户输入类型：double用于命令行程序

1 个答案: