pre incrementing数组对象（++ frequency [i];）是什么意思？

Question

public class ArrayStudentPoll { 
    public static void main(String args[]) 
    { 
     // array of survey responses 
     int responses[] = { 1, 2, 6, 4, 8, 5, 9, 7, 8, 10, 1, 6, 3, 8, 6, 
     10, 3, 8, 2, 7, 6, 5, 7, 6, 8, 6, 7, 5, 6, 6, 5, 6, 7, 5, 6, 
     4, 8, 6, 8, 10 }; 
     int frequency[] = new int[ 11 ]; // array of frequency counters 

     // for each answer, select responses element and use that value 
     // as frequency index to determine element to increment 
     for (int answer = 0; answer < responses.length; answer++) 
      ++frequency[ responses[ answer ] ]; 


     System.out.printf("%s%10s\n", "Rating", "Frequency"); 

     // output each array element's value 
     for (int rating = 1; rating < frequency.length; rating++) 
      System.out.printf("%6d%10d\n", rating, frequency[ rating ]); 
    } 
} 

这是我在我的项目中看到的代码。

我所了解的一切，但部分++frequency[i];频率是一个数组而不是数字？那究竟是在做什么？他们写了评论，但仍然没有得到他们。

这里是我失控它

Rating Frequency 
    1   2 
    2   2 
    3   2 
    4   2 
    5   5 
    6  11 
    7   5 
    8   7 
    9   1 
    10   3 

Answer 1

++frequency[responses[answer]]预增量responses[answer]“日的frequency阵列的元件的结果。

这相当于

frequency[responses[answer]] = frequency[responses[answer]] + 1; 

BTW，使用后的增量（frequency[responses[answer]]++）将给予同样的结果在这个程序中，由于增量运算符的返回值不使用此代码。