package set;

import java.util.HashMap;
import java.util.TreeMap;

public class TreeMapDemo {
	public static void main(String[] args) {
		//統計一個字串中每個字元出現的次數
		String str = "aaabbccm";
		//1.字串轉陣列
		char [] arr = str.toCharArray();
		//2.建立map
		HashMap<Character,Integer> hm = new HashMap<>();
		//3.遍歷陣列key-value
		for (char c : arr) {
			//4.每取出一個元素，判斷key是否存在
			if(!hm.containsKey(c)){
				//5.若不存在，存入key，value=1
				hm.put(c, 1);
			}else{
				//6.若存在，value+1
				hm.put(c, hm.get(c)+1);
			}
		}
		System.out.println(hm);
	}
}