Swift 编译错误“未知类型名称”和“预期类型”

在使用 Swift 进行编程开发的过程中，经常会遇到一些编译错误。其中两个常见的错误是“未知类型名称”和“预期类型”。这些错误提示可能会让初学者感到困惑，但实际上它们是编译器在编译代码时发现的问题的指示。

swift
class Person {
    var name: String
    var age: Int
    
    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }
}

swift
let person = Person(name: "John", age: 30)
print(person.name)
print(person.age)

swift
import UIKit

swift
class Person {
    var name: String
    var age: Int
    
    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }
}

swift
let number1 = 10
let number2 = 5
let result = number1 + number2
print(result)

swift
let number1 = 10
let number2 = 5
let result = number1 + number2
print(result)

swift
let number = 10
let string = String(number)
print(string)