javascript - 反转短语中的某些单词

Question

我正在尝试颠倒句子中的每个第二个单词。即第 2、4、6、8、.. 词。这是我到目前为止所得到的，我只是无法正确设置计数器。我的话都被颠倒了，而不是我想要的。我仍然处于 javascript 的基础知识中，使用函数和数组会更容易解决这个问题，但我不能使用它们。

var str=prompt("Enter")
var length=str.length;    
var sentence="";    
var word = "";    
var counter = 1;

for(var i=0; i < length; i++) {   
    if (counter = 2){    
      if (str.charAt(i) != ' '){    
        word = str.charAt(i) + word;
        counter = 1
      }else {
        sentence += word +" ";
        word = "";
        counter=2
      }
   }
}

sentence += word;    
alert("the result is: "+sentence);

Answer 1

像这样的东西应该可以解决问题:

http://jsfiddle.net/QP4fL/5/

这是一个冗长的长篇大论，但它完全符合您的要求，没有一些您说您不能以最简单的语法可能使用的运算符:

var str="Test to make sure that this is working.";
var length=str.length;    
var sentence="";    
var word = "";   
var counter = 0;

for(var i=0; i < length; i++) {
    if(str[i]===" " && counter === 1){
        sentence += word+" ";
        counter = 0; word = "";
    } else if(str[i]===" " && counter === 0){
        sentence += word+" ";
        counter++; word = "";
    } else if(length-1 === i){
        word += str[i];
        sentence += word;
    } else if(counter === 1) {
        word = str[i] + word;
    } else {
        word += str[i];
    }
}

alert("the result is: "+sentence);

评论解释:

/* Define our base variables. We need a few things. A string to test,
the length of the string, what our sentence will end up being, a temp
word variable, and a counter to determine odds/etc. */

var str=prompt("Enter: ");
var length=str.length;    
var sentence="";    
var word = "";   
var counter = 0;

/* Typical for loop for every character in the string you provided. */
for(var i=0; i < length; i++) {

// Now we need to know a few things, as I'll discuss as we get to them.

/* First check. If we encounter a " " AND the counter is at 1 (meaning
we are at the second find of a " ", we want to add the word to our sentence
plus an additional space to make up for the lack of catching the " ". 
Furthermore, we need to reset our counter and our word variables. */
if(str[i]===" " && counter === 1){
    sentence += word+" ";
    counter = 0; word = "";

/* Second check. If we encounter a " " but the counter is still at 0,
we want to increment counter and add the word normally. Also, reset
the word. */

} else if(str[i]===" " && counter === 0){
    sentence += word+" ";
    counter++; word = "";

 /* Third check. If we encounter the end of our string, we may as well
 just print our word as is. */
} else if(length-1 === i){
    word += str[i];
    sentence += word;

 /* Fourth check. If we encounter a series of letters where the counter
 is at 1, we can reverse the string by adding `str[i]` BEFORE the current
 word string. This will ensure the NEW characters precede the EXISTING ones. */
} else if(counter === 1) {
    word = str[i] + word;

// And, if none of the above is true, just add the letter to our word string.
} else {
    word += str[i];
}
}

alert("the result is: "+sentence);