把Math.PI中的数字，按照出现顺序打印出来，相同数字，只出现一次

package com.dzqc.Day0125;

/**
 * Created with IntelliJ IDEA.
 *
 * @Author: zhangxiaokun
 * @Date: 2022/01/25/17:21
 * @Description:
 * 把Math.PI中的数字，按照出现顺序打印出来，相同数字，只出现一次
 */
public class Zuoye {

    public static void main(String[] args) {
        double PI = Math.PI;
        String str = String.valueOf(PI);
        String[] nums = str.split("\\.");
        String s = "";
        for (int i = 0; i < nums.length; i++) {
            String b = nums[i];
            s = s + b;
        }

        System.out.println("原始数字");
        System.out.println(s);

        StringBuilder stringBuilder = new StringBuilder(s);
        for (int i = 0; i < stringBuilder.length() - 1; i++) {
            for (int j = i + 1; j < stringBuilder.length(); j++) {
                if (stringBuilder.charAt(i) == stringBuilder.charAt(j)) {
                    stringBuilder.deleteCharAt(j);
                    j--;
                }
            }
        }

        System.out.println("去重之后的数字" + stringBuilder);
    }

}