Javascript编码测验不加起来

Question

我想要做一个简单的测验，它应该总结正确的答案和不正确的答案。事情是，虽然我把三个正确的答案中的两个，我仍然得到正确和不正确的数组相同的结果：0.因此，在评估函数中，最后肯定会出现错误。在此先感谢

var responsesArray= []; 
 
var correct=[]; 
 
var incorrect= []; 
 

 

 

 

 
function question2() { 
 

 
    var firstQuestion = prompt('Does null === 0 ? (Yes or No)') 
 

 
// why do you need to convert the answer to lowercase? 
 
    if (firstQuestion.toLowerCase() === 'yes') { 
 
    firstQuestion = true 
 
    } else if (firstQuestion.toLowerCase() === 'no') { 
 
    firstQuestion = false 
 
    } else { 
 
// what if the user writes something other than yes or no? 
 
// they will have to answer the question again 
 
    alert("Please answer either Yes or No"); 
 
    return question2(); 
 
    } 
 
    responsesArray.push(firstQuestion); // add the true or false value to the responses array 
 
} 
 

 
question2(); 
 

 

 

 
function question3() { 
 
    var js = prompt('What was the original name for JavaScript: Java, LiveScript, JavaLive, or ScriptyScript?'); 
 
    js = js.toLowerCase(); 
 
    switch (js) { 
 
    // your own answers 
 
    
 
    case "livescript": 
 
    console.log("Correct!"); 
 
    break; 
 
    case "Java": 
 
    console.log("wrong"); 
 
    break; 
 
    case "JavaLive": 
 
    console.log("wrong"); 
 
    break; 
 
    case "ScriptyScript": 
 
    console.log("wrong"); 
 
    break; 
 
    default: 
 
    console.log("Sorry the answer is LiveScript"); 
 
    } 
 
    responsesArray.push(js); 
 
    
 
    var mine = prompt('What coding language is exclusively related to the back-end: Ruby, JavaScript, HTML?'); 
 
    mine= mine.toLowerCase(); 
 
    switch (mine) { 
 
    // your own answers 
 
    \t case "ruby": 
 
    console.log("Yeah!"); 
 
    break; 
 
    case "html": 
 
    console.log("ouuu I'm sorry for you"); 
 
    break; 
 
    case "javascript": 
 
    console.log("Yeah but so so"); 
 
    break; 
 
    } 
 
    responsesArray.push(mine); 
 
} 
 

 
question3(); 
 

 
function evaluate(responsesArray) 
 
{ 
 

 
for (var i = 0; i < responsesArray.length; i++) 
 
\t { 
 
\t \t if (responsesArray[i] === true|| "livescript" || "ruby") 
 
    { 
 
     correct++; 
 

 
    } else{ 
 
     if (responsesArray[i] !== true|| "livescript" || "ruby") { 
 
     incorrect++; 
 
    } 
 
\t } 
 
}

Answer 1

定义的数组存储了正确的答案，然后比较正确和用户的反应，并且很容易确定其是否正确。

请检查下面的代码段。

var responsesArray= []; 
 
var correct=0; 
 
var incorrect= 0; 
 
//Correct answer key initialize 
 
var index = 0; 
 
//Initialize array to store correct answer. 
 
var correctAnswers = []; 
 

 

 
function question2() { 
 
    //Save correct answer. 
 
    correctAnswers[index++] = "yes"; 
 
    var firstQuestion = prompt('Does null === 0 ? (Yes or No)') 
 

 
    // why do you need to convert the answer to lowercase? 
 
    if (firstQuestion.toLowerCase() === 'yes') { 
 
    console.log("correct"); 
 
    firstQuestion = 'yes' 
 
    } else if (firstQuestion.toLowerCase() === 'no') { 
 
    console.log("in-correct"); 
 
    firstQuestion = 'no' 
 
    } else { 
 
    // what if the user writes something other than yes or no? 
 
    // they will have to answer the question again 
 
    alert("Please answer either Yes or No"); 
 
    return question2(); 
 
    } 
 
    responsesArray.push(firstQuestion); // add the true or false value to the responses array 
 
} 
 

 
question2(); 
 

 

 

 
function question3() { 
 
    //Save correct answer. 
 
    correctAnswers[index++] = "livescript"; 
 
    var js = prompt('What was the original name for JavaScript: Java, LiveScript, JavaLive, or ScriptyScript?'); 
 
    js = js.toLowerCase(); 
 
    switch (js) {  
 
     // your own answers 
 

 
    case "livescript": 
 
     console.log("Correct!"); 
 
     break; 
 
    case "Java": 
 
     console.log("wrong"); 
 
     break; 
 
    case "JavaLive": 
 
     console.log("wrong"); 
 
     break; 
 
    case "ScriptyScript": 
 
     console.log("wrong"); 
 
     break; 
 
    default: 
 
     console.log("Sorry the answer is LiveScript"); 
 
    } 
 
    responsesArray.push(js); 
 
    
 
    //Save correct answer. 
 
    correctAnswers[index++] = "ruby"; 
 
    var mine = prompt('What coding language is exclusively related to the back-end: Ruby, JavaScript, HTML?'); 
 
    mine= mine.toLowerCase(); 
 
    switch (mine) { 
 
     // your own answers 
 
    case "ruby": 
 
     console.log("Yeah!"); 
 
     break; 
 
    case "html": 
 
     console.log("ouuu I'm sorry for you"); 
 
     break; 
 
    case "javascript": 
 
     console.log("Yeah but so so"); 
 
     break; 
 
    } 
 
    responsesArray.push(mine); 
 
    //Call function to evaluate correct or incorrect answer 
 
    evaluate(responsesArray,correctAnswers) 
 
} 
 

 
question3(); 
 

 
function evaluate(responsesArray,correctAnswers) 
 
{ 
 
    for (var i = 0; i < responsesArray.length; i++) 
 
    { 
 
    //Match response with correct answer. 
 
    if (responsesArray[i] === correctAnswers[i]) 
 
    { 
 
     correct++; 
 

 
    } else{ 
 
     if (responsesArray[i] !== correctAnswers[i]) { 
 
     incorrect++; 
 
     } 
 
    } 
 
    } 
 
    alert("Correct : "+correct+" and Incorrect : "+incorrect); 
 
}

Answer 2

您测试正确答案的方式是错误的。相反，用正确的答案定义数组，然后确认如下：

var correct = incorrect = 0; // better initialise your variables 

function evaluate(responsesArray) { 
    var correctAnswers = [true,"livescript","ruby"]; 
    for (var i = 0; i < responsesArray.length; i++) { 
    if (responsesArray[i] === correctAnswers[i]) { 
     correct++; 
    } else { 
     incorrect++; 
    } 
    } 
} 

你有什么：

if (responsesArray[i] === true|| "livescript" || "ruby"){ 

但是，这意味着：

if the answer was true, or .... "livescript" is true, or ... "ruby" is true, then 

如JavaScript认为字符串是truthy，if条件将始终为真。

还要注意有没有必要做第二if，因为如果第一if条件是假的，这意味着你已经筛选那些答案是错的情况下，else部分时，才会执行。

最后，你的计数器变量应该在开始递增之前定义。它的工作原理没有这个定义，但是如果两个变量中的一个没有增加，在你致电evaluate后，它仍然是未定义的。最好总是定义你的变量。