What exactly does ++array[s.charAt(i) - 'A'] do?

Question

for (int i = 0; i < s.length(); ++i) 
    {
        if (s.charAt(i) >= \'A\' && s.charAt(i) <= \'Z\') 
        {
            ++array[s.charAt(i) - \         


        

Answer 1

What is count[str.charAt(i)]++ actually storing? [duplicate] for those guys who have the same related question here is the answer

First

static final int chars=256; static char count[]=new char[chars];

when we change this code into image it become like this

0 1 2 3 4 5 6 7 8 9 .. .. .. .. .. .. .. 97 .. 255

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Second

count[str.charAt(i)]++;

Let say you have str = “abc” Then str.charAt(0) will be “a” Then count[‘a’] means count[97] why? Because java automatically converted ‘a’ into ASCII code number 97; Then count[97] value is 0 when you increment it like this count[97]++ then it will become 1

0 1 2 3 4 5 6 7 8 9 .. .. .. .. .. .. .. 97 .. 255

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0

if you increment it again like count[97]++ then it will become 2.

0 1 2 3 4 5 6 7 8 9 .. .. .. .. .. .. .. 97 .. 255

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0

That is the whole the secret behind. I do not describe the rest because I think your question is answered. If you want to test what I said is correct check it using this simple code

public static void main(String[] argv) {

 int[] count = new int[255]; 
    count['a']++;
    System.out.println(count['a']);
    int counter=0;
    for(int i=0;i

}