PAS/src/main/java/cn/cslg/pas/common/utils/MathUtils.java

package cn.cslg.pas.common.utils;

import java.math.BigDecimal;
import java.util.List;

/**
 * @Author chenyu
 * @Date 2023/3/28
 */
public class MathUtils {
    private static final String[] DIGITS = {"零", "一", "二", "三", "四", "五", "六", "七", "八", "九"};
    private static final String[] UNITS = {"", "十", "百", "千"};

    public static double saveTwoDecimal(double value) {
        BigDecimal bd = new BigDecimal(value);
        value = bd.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
        return value;
    }

    public static String fun(int n, int num) {
        // n 表示目标进制, num 要转换的值
        String str = "";
        int yushu;      // 保存余数
        int shang = num;      // 保存商
        while (shang > 0) {
            yushu = shang % n;
            shang = shang / n;

            // 10-15 -> a-f
            if (yushu > 9) {
                str = (char) ('a' + (yushu - 10)) + str;
            } else {
                str = yushu + str;
            }
        }

        return str;
    }

    public static int BinaryToDecimal(int binaryNumber) {

        int decimal = 0;
        int p = 0;
        while (true) {
            if (binaryNumber == 0) {
                break;
            } else {
                int temp = binaryNumber % 10;
                decimal += temp * Math.pow(2, p);
                binaryNumber = binaryNumber / 10;
                p++;
            }
        }
        return decimal;
    }

    public static Integer getNotNullMinNum(List<Integer> nums) {
        Integer min = 100000;
        for (Integer i : nums) {
            if (i != null) {
                if (i < min) {
                    min = i;
                }
            }
        }
        return min;
    }

    public static String numberToChinese(int num) {
        if (num == 0) {
            return "零";
        }

        StringBuilder result = new StringBuilder();
        String numStr = Integer.toString(num);
        int length = numStr.length();
        boolean prevZero = false; // 标记前一个字符是否为零

        for (int i = 0; i < length; i++) {
            int digit = numStr.charAt(i) - '0';
            int unitIndex = length - i - 1; // 计算单位位置（从高位开始）

            if (digit == 0) {
                prevZero = true;
            } else {
                if (prevZero) {
                    result.append(DIGITS[0]);
                    prevZero = false;
                }
                result.append(DIGITS[digit]);
                if (unitIndex > 0) { // 个位不添加单位
                    result.append(UNITS[unitIndex]);
                }
                prevZero = false;
            }
        }

        String str = result.toString();

        // 处理十位为1的特殊情况（10-19）
        if (str.startsWith("一十") && str.length() > 1) {
            str = str.substring(1);
        }

        // 清理多余零
        str = str.replaceAll("零+", "零");
        if (str.endsWith("零")) {
            str = str.substring(0, str.length() - 1);
        }

        return str;
    }

    public static String convertToChinese(int num) {
        if (num < 0 || num > 100) {
            return "";
        }
        if (num == 0) {
            return "零";
        }
        if (num == 100) {
            return "一百";
        }

        int ten = num / 10;
        int unit = num % 10;
        StringBuilder result = new StringBuilder();

        // 处理十位
        if (ten > 0) {
            if (ten > 1) { // 十位大于1时需添加数字
                result.append(DIGITS[ten]);
            }
            result.append("十");
        }

        // 处理个位
        if (unit > 0 || ten == 0) { // 个位为0且十位存在时不处理，否则需添加
            result.append(DIGITS[unit]);
        }

        return result.toString();
    }
}