Write a function charCount() to count the characters code example

Example 1: count letters numbers and characters

public static String countLetter(String str){
    String abc=str;
    int a=0,b=0;
    while(str.length()>0){
        int i=0;
        String ch=str.substring(i,i+1);
        if(ch.matches(".*[a-zA-Z].*")){
            a++;
        }else if (ch.matches(".*[0-9].*")){
            b++;
        }
        str=str.substring(i+1);
    }
    return abc + " has "+a+" letters "+b+" digit 
          and "+(abc.length()-(a+b))+" other characters ";
      
      
OR+++++++++++++++++++++++++++++++++
      
      
  static void findSum(String str)
{
   int total= str.length();
   str = str.replaceAll("\\s", "");
   int num =0;
   int letter=0;
   int i=0;
   while(i "+num +
                      " numbers -> "+ (total-letter-num) + " other chars");
}

Example 2: count characters in string

# count characters iterative
def count_chars(s)
  count = Hash.new(0)
  s.split("").each do |x|
    count[x] += 1
  end
  count
end

# count characters functional
s.chars.map {|c| [c, s.chars.count(c)] }.to_h