interface Person {
    firstName: string,
    lastName: string
}

function greeter(person: Person) {
    return person.firstName + " " + person.lastName;
}

var user = {firstName: 'Jane', lastName: 'User'};
console.log(greeter(user));

class Student {
    fullName: string;
    // 构造函数参数中使用public是一种简写形式，它将自动创建具有该名称的属性
    constructor(public firstName, public middleInitial, public lastName) {
        this.fullName = firstName + " " + middleInitial + " " + lastName;
    }
}

interface Person {
    firstName: string,
    lastName: string
}

function greeter(person:Person) {
    return person.firstName + " " + person.lastName;
}

var student = new Student('Jane', 'M', 'User');
console.log(greeter(student));