为什么需要重复减去1？(Why does quot need to be repeatedly subtracted by 1?)

 这个问题是基于这个线程编程之谜：你如何将Excel列名转换为数字？ 
 
 以下是将该列号转换为excel列名称的问题的代码 
 
public String getColName (int colNum) {

   String res = "";
   int quot = colNum;
   int rem;        
    /*1. Subtract one from number.
    *2. Save the mod 26 value.
   *3. Divide the number by 26, save result.
   *4. Convert the remainder to a letter.
   *5. Repeat until the number is zero.
   *6. Return that bitch...
   */
    while(quot > 0)
    {
        quot = quot - 1;
        rem = quot % 26;
        quot = quot / 26;

        //cast to a char and add to the beginning of the string
        //add 97 to convert to the correct ascii number
        res = (char)(rem+97) + res;            
    }   
    return res;
}
 
 我彻底测试了这段代码并且它可以正常工作，但是我有一个问题，为什么这条线需要重复才能工作 
 
            quot = quot - 1;
 
 根据我的理解，需要使用quot来将col编号映射到远离'a'的距离。 这意味着1应该映射到距离'a'的距离为0，距离'a'的距离为2到1，依此类推。 但是你不需要减去这一次来解释这一点吗？ 不是循环，我的意思是最终， 
 
            quot = quot / 26;
 
 将停止循环。 

This question is based off this thread Programming Riddle: How might you translate an Excel column name to a number?
 
Here is code from that question to translate a column number to an excel column name
 
public String getColName (int colNum) {

   String res = "";
   int quot = colNum;
   int rem;        
    /*1. Subtract one from number.
    *2. Save the mod 26 value.
   *3. Divide the number by 26, save result.
   *4. Convert the remainder to a letter.
   *5. Repeat until the number is zero.
   *6. Return that bitch...
   */
    while(quot > 0)
    {
        quot = quot - 1;
        rem = quot % 26;
        quot = quot / 26;

        //cast to a char and add to the beginning of the string
        //add 97 to convert to the correct ascii number
        res = (char)(rem+97) + res;            
    }   
    return res;
}
 
I tested this code thoroughly and it works but I have a question about what this line needs to be repeated for this to work 
 
            quot = quot - 1;
 
From my understanding the quot is needed to map the col number to distance away from 'a'. That means 1 should map to 0 distance from 'a', 2 to 1 distance away from 'a' and so on. But don't you need to subtract this one once to account for this? Not in a loop I mean eventually,
 
            quot = quot / 26;
 
will stop the loop.

原文：https://stackoverflow.com/questions/28119064