Question

我一直在尝试在Codecademy上解决这个问题。我所做的一切似乎都没有用。

说明： “在你的案例中添加一些if / else语句，检查一个条件和另一个条件是否为真，以及一个条件或另一个条件是否为真。每次至少使用＆amp;＆amp;和||一次。”

这是我之前输入的代码：

var user = prompt("What is your name?").toUpperCase();

switch(user) {
    case 'Sam':
        console.log("Hi, Sam");
        break;
    case 'John':
        console.log("Hi, John");
        break;
    case 'Mary':
        console.log("Hi, Mary");
        break;
    default:
        console.log("I don't know you. What is your name?");
}

Answer 1

您的代码没有任何if/else语句。这样的事情怎么样：

var user = prompt("What is your name?").toUpperCase();

// If user is known, greet him
if (user === "SAM" || user === "JOHN" || user === "MARY") {
  console.log("Hi, " + user)
}
// Otherwise apologize because we are polite
else {
  console.log("Sorry " + user + ", I don't know you.");
}

// If user is neither John nor Sam, ask about them
if (user !== "JOHN" && user !== "SAM") {
  console.log("By the way, how are John and Sam doing?");
}

Answer 2

.toUpperCase()将字符串转换为大写字母，因此它将是“SAM”，“JOHN”等。

将其更改为：

String.prototype.capitalizeFirstLetter = function() {
    return this.charAt(0).toUpperCase() + this.slice(1);
}

var user = prompt("What is your name?").capitalizeFirstLetter()

您需要测试什么条件？

switch(user) {
case 'Sam':
    if ( someCondition || anotherCondition ) { 
            // do something
    } else { // do something 
    }
    console.log("Hi, Sam");
    break;

case 'John':
    console.log("Hi, John");
    break;

case 'Mary':
    console.log("Hi, Mary");
    break;

default:
    console.log("I don't know you. What is your name?”);
}

如何添加逻辑运算符？

2 个答案: