大数的加减乘除

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大数的加减乘除
package com.test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class BigInt {
    /**
     * 
     * 
     * 
     */
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub 
        BufferedReader stdin = new BufferedReader(new InputStreamReader(
                System.in));
        String num1 = "";
        String num2 = "";
        boolean isill = true;// 判断输入的值是否合法 
        do {
            System.out.println("输入第一串数字：");
            num1 = stdin.readLine();
            if (num1.length() == 0)// 如果没输入，则提示重新输入 
            {
                isill = false;
                System.out.println("输入的数字有误！");
            }
            if (num1.length() == 1)// 如果输入的是1个字符，则必须是0-9数字 
            {
                if (num1.matches("[0-9]") == false) {
                    isill = false;
                    System.out.println("输入的数字有误！");
                }
            }
            else {
                if (num1.matches("[-]*[1-9][0-9]*") == false)// 判断输入的字符串是否是非0开头的数字 
                {
                    isill = false;
                    System.out.println("输入的数字有误！");
                }
            }// end else 
        }// end do 
        while (isill == false);// 如果输入有误，则继续输入 
        do {
            System.out.println("输入第二串数字：");
            num2 = stdin.readLine();
            // System.out.println("num2的长度"+num2.length()); 
            if (num2.length() == 0)// 如果没输入，则提示重新输入 
            {
                isill = false;
                System.out.println("输入的数字有误！");
                // continue; 
            }
            if (num2.length() == 1)// 如果输入的是1个字符，则必须是0-9数字 
            {
                if (num2.matches("[1-9]") == false) {
                    isill = false;
                    System.out.println("输入的数字有误！");
                    // continue; 
                }
            }
            else {
                if (num2.matches("[-]*[1-9][0-9]*") == false)// 判断输入的字符串是否是非0开头的数字 
                {
                    isill = false;
                    System.out.println("输入的数字有误！");
                    // continue; 
                }
            }
        } while (isill == false);// 如果输入有误，则继续输入 
        BigInt bi = new BigInt();
        if (num1.charAt(0) == '-' && num2.charAt(0) != '-')// 如果前者是负数,后者是正数 
        {
            System.out.println("两数之和：(" + num1 + ")+(" + num2 + ")="
                    + bi.sub(num2, num1.substring(1, num1.length())));// 输出两数相加结果 
            System.out.println("两数之差：(" + num1 + ")-(" + num2 + ")=" + "-"
                    + bi.add(num1.substring(1, num1.length()), num2));// 输出两数相减结果 
            System.out.println("两数之积：(" + num1 + ")*(" + num2 + ")=" + "-"
                    + bi.mult(num1.substring(1, num1.length()), num2));// 输出两数相乘结果 
            String[] div = bi.div(num1.substring(1, num1.length()), num2);
            System.out.println("两数相除：(" + num1 + ")/(" + num2 + ")  商=" + "-"
                    + div[0] + ",余数=" + div[1]);// 输出两数相除结果 
        }
        if (num1.charAt(0) != '-' && num2.charAt(0) == '-')// 如果前者是正数,后者是负数 
        {
            System.out.println("两数之和：(" + num1 + ")+(" + num2 + ")="
                    + bi.sub(num1, num2.substring(1, num2.length())));// 输出两数相加结果 
            System.out.println("两数之差：(" + num1 + ")-(" + num2 + ")="
                    + bi.add(num1, num2.substring(1, num2.length())));// 输出两数相减结果 
            System.out.println("两数之积：(" + num1 + ")*(" + num2 + ")=" + "-"
                    + bi.mult(num1, num2.substring(1, num2.length())));// 输出两数相乘结果 
            String[] div = bi.div(num1, num2.substring(1, num2.length()));
            System.out.println("两数相除：(" + num1 + ")/(" + num2 + ") 商=" + "-"
                    + div[0] + ",余数=" + div[1]);// 输出两数相除结果 
        }
        if (num1.charAt(0) == '-' && num2.charAt(0) == '-')// 如果前者是负数,后者是负数 
        {
            System.out.println("两数之和：("
                    + num1
                    + ")+("
                    + num2
                    + ")="
                    + "-"
                    + bi.add(num1.substring(1, num1.length()), num2.substring(
                            1, num2.length())));// 输出两数相加结果 
            System.out.println("两数之差：("
                    + num1
                    + ")-("
                    + num2
                    + ")="
                    + bi.sub(num2.substring(1, num2.length()), num1.substring(
                            1, num1.length())));// 输出两数相减结果 
            System.out.println("两数之积：("
                    + num1
                    + ")*("
                    + num2
                    + ")="
                    + bi.mult(num1.substring(1, num1.length()), num2.substring(
                            1, num2.length())));// 输出两数相乘结果 
            String[] div = bi.div(num1.substring(1, num1.length()), num2
                    .substring(1, num2.length()));
            System.out.println("两数相除：(" + num1 + ")/(" + num2 + ") 商=" + div[0]
                    + ",余数=" + div[1]);// 输出两数相除结果 
        }
        if (num1.charAt(0) != '-' && num2.charAt(0) != '-')// 全正数 
        {
            System.out.println("两数之和：(" + num1 + ")+(" + num2 + ")="
                    + bi.add(num1, num2));// 输出两数相加结果 
            System.out.println("两数之积：(" + num1 + ")*(" + num2 + ")="
                    + bi.mult(num1, num2));// 输出两数相乘结果 
            System.out.println("两数之差：(" + num1 + ")-(" + num2 + ")="
                    + bi.sub(num1, num2));// 输出两数相减结果 
            String[] div = bi.div(num1, num2);
            System.out.println("两数相除：(" + num1 + ")/(" + num2 + ") 商=" + div[0]
                    + ",余数=" + div[1]);// 输出两数相除结果 
        }
        // System.out.println(num1+" " +num2); 
        // System.out.println(bi.split(num1).toString()+bi.split(num2).toString()); 
    }
    // 统一长度，将返回补了0以后的数组 
    String length(String num, int length)// num个数小的字符串，length相差的个数 
    {
        String count0 = "";// 需要补0的个数 
        for (int i = 0; i < length; i++) {
            count0 += "0";
        }
        return count0 + num;
    }
    
    
    
    
    
    // 加运算 num1+num2 
    String add(String num1, String num2) {
        // num1 = num1.substring(1); 
        if (num1.length() >= num2.length())// 如果第一个字符串比较短，则将它补0 
        {
            num2 = length(num2, num1.length() - num2.length());
        }
        else
            num1 = length(num1, num2.length() - num1.length());
        int length = num1.length();// 长度统一以后，取第一个数的长度 
        int j, k = 0;// 临时保存两个位上要计数的值 
        String result = "";// 结果 
        int jinwei = 0;// 保存进位，0表示没进位，1表示进位为1 
        for (int i = length - 1; i >= 0; i--) {
            int num;// 相加以后位置要显示的数值 
            j = Integer.parseInt(String.valueOf(num1.charAt(i)));
            k = Integer.parseInt(String.valueOf(num2.charAt(i)));
            if (j + k + jinwei >= 10 && i != 0) {
                num = j + k + jinwei - 10;
                jinwei = 1;
            } else {
                num = j + k + jinwei;
                jinwei = 0;
            }
            result = String.valueOf(num) + result;
        }
        // System.out.println(result); 
        return result;
    }
    
    
    
    
    
    // 乘法运算，并且将num1作为乘数，num2为被乘数 即num2*num1 
    String mult(String num1, String num2) {
        int length1 = num1.length();// 第一个字符串长度 
        int length2 = num2.length();// 第二个字符串长度 
        int temp1, temp2;// 临时保存两个位置上要乘积的值 
        int jinwei = 0;// 保存进位默认为1 
        String[] mult1 = new String[length1];// 保存每位乘积以后的结果，并且将num1作为乘数 
        String count0 = "";// 保存计数后面需要加的0的个数 
        for (int i = length1 - 1; i >= 0; i--) {// 将num1作为乘数 
            int num;// 保存当前位应该显示数的数值 
            mult1[length1 - i - 1] = "";// 为每个数组附初值 
            for (int k = i; k < length1 - 1; k++)// 每移动一位，则在后面加一个0，即判断i到length1-1的距离 
            {
                count0 += "0";
            }
            temp1 = Integer.parseInt(String.valueOf(num1.charAt(i)));// 乘数的第i位 
            // 用乘数的第i位去乘被乘数的每一位 
            for (int j = length2 - 1; j >= 0; j--) {
                temp2 = Integer.parseInt(String.valueOf(num2.charAt(j)));
                if (temp1 * temp2 + jinwei >= 10) {
                    num = (temp1 * temp2 + jinwei) % 10;
                    jinwei = (temp1 * temp2 + jinwei) / 10;
                    // System.out.println("每位上要显示的数值："+num); 
                } else {
                    num = temp1 * temp2 + jinwei;
                    jinwei = 0;
                    // System.out.println("每位上要显示的数值："+num); 
                }
                mult1[length1 - i - 1] = String.valueOf(num)
                        + mult1[length1 - i - 1];
                // System.out.println(mult1[length1-i-1]); 
            }
            // 每组乘积以后，如果 进位不为0，则将进位放在当前字符串的最前面,然后将进位清0 
            if (jinwei != 0) {
                mult1[length1 - i - 1] = String.valueOf(jinwei)
                        + mult1[length1 - i - 1];
                jinwei = 0;
            }
            mult1[length1 - i - 1] += count0;// 在每次乘积的后面补上0的个数 
            count0 = "";// 每组数据加完0以后，将count0制空 
            // System.out.println("所有要相加的值：" + mult1[length1 - i - 1]); 
        }
        for (int i = 0; i < length1 - 1; i++)// 将每位乘积以后的数组，进行两两用add方法来求值，并将相加以后的结果保存在后面一个数组中 
        {
            mult1[i + 1] = add(mult1[i], mult1[i + 1]);
            // System.out.println("每次两两相加结果：" + mult1[i + 1]); 
        }
        return mult1[length1 - 1];// 依次求和以后，只要返回数组中的最后一个元数，便是乘积以后的值 
    }
    // 两数相减,其中num1为被减数，num2为减数 即num1-num2 
    String sub(String num1, String num2) {
        String str = "";// 结果中正负数标志 
        int length1 = num1.length();
        int length2 = num2.length();
        String bignum = num1;// 假定第一个数为大数，第二个数为小数 
        String smallnum = num2;
        if (length1 < length2)// 如果num1的长度 小于num2的长度，则结果为负数 
        {
            str = "-";
            bignum = num2;
            smallnum = num1;
        }// end if(length1 < length2) 
        if (length1 == length2)// 如果num1的长度和num2的长度相同,则比较每位数值 
        {
            // 用compareTo来比较那个字符串比较大 
            if (num1.compareTo(num2) > 0)// num1>num2 
            {
                bignum = num1;
                smallnum = num2;
            } else if (num1.compareTo(num2) < 0)// num1<num2 
            {
                bignum = num2;
                smallnum = num1;
                str = "-";
            }
            else
                // num1 == num2 
                return "0";
            /*
             * 按位比较两个字符串的大小 int temp1 = 0, temp2 = 0;// 临时保存每位上的两个数值
             * 
             * int i;// 计数 for (i = 0; i < length1; i++) { temp1 =
             * Integer.parseInt(String.valueOf(num1.charAt(i))); temp2 =
             * Integer.parseInt(String.valueOf(num2.charAt(i))); if (temp1 <
             * temp2)// 如果第i位上 第1个数值比第2个数值小，则结果为负数，跳出循环 { str = "-"; bignum =
             * num2; smallnum = num1; break; }// end if(temp1 < temp2) else //
             * 如果第i位上，第1个数值>=第2个数值，则继续下一位比较 continue; }// end for
             * 
             * if (i == length1 && (temp1 == temp2))// 如果每位上的数值都相同，则结果为0，直接输出 {
             * return "0"; }
             */
        }// end if(length1 == length2) 
        int jinwei = 0;// 保存进位 
        int temp1, temp2;// 临时保存每位上要相减的两个数值 
        smallnum = length(smallnum, bignum.length() - smallnum.length());
        String result = "";// 结果 
        int length = bignum.length();// 统一长度以后的字符串长度 
        for (int i = length - 1; i >= 0; i--) {
            int num = -1;// 相加以后位置要显示的数值 
            temp1 = Integer.parseInt(String.valueOf(bignum.charAt(i)));
            temp2 = Integer.parseInt(String.valueOf(smallnum.charAt(i)));
            // System.out.println("temp1:"+ temp1 + "," + "temp2:" + temp2); 
            if (jinwei == 0) {
                if (temp1 - temp2 < 0) {
                    jinwei = 1;
                    num = (temp1 - temp2 + 10) % 10;
                    // System.out.println("每位上要显示的值0,<0：" + num); 
                    result = String.valueOf(num) + result;
                    continue;
                }
                if (temp1 - temp2 == 0) {
                    jinwei = 0;
                    num = temp1 - temp2;
                    // System.out.println("每位上要显示的值0,0：" + num); 
                    result = String.valueOf(num) + result;
                    continue;
                }
                if (temp1 - temp2 > 0) {
                    jinwei = 0;
                    num = temp1 - temp2;
                    // System.out.println("每位上要显示的值0,>0：" + num); 
                    result = String.valueOf(num) + result;
                    continue;
                }
            }
            if (jinwei == 1) {
                if (temp1 - temp2 < 0) {
                    num = (10 + (temp1 - temp2 - jinwei)) % 10;
                    jinwei = 1;
                    // System.out.println("每位上要显示的值1,<0：" + num); 
                    result = String.valueOf(num) + result;
                    continue;
                }
                if (temp1 - temp2 == 0) {
                    num = 10 - jinwei - (temp1 - temp2);
                    jinwei = 1;
                    // System.out.println("每位上要显示的值1,0：" + num); 
                    result = String.valueOf(num) + result;
                    continue;
                }
                if (temp1 - temp2 > 0) {
                    num = temp1 - temp2 - jinwei;
                    jinwei = 0;
                    // System.out.println("每位上要显示的值1,>0：" + num); 
                    result = String.valueOf(num) + result;
                    continue;
                }
            }
        }
        // 删除结果中前面为0的数字 
        while ('0' == (result.charAt(0))) {
            result = result.substring(1);
            // System.out.println("少了一个0："+result); 
            if ('0' != (result.charAt(0)))
                break;
        }
        result = str + result;// 加上正负数标志 
        // System.out.println(str); 
        return result;
    }
    // 除法,其中num1为被除数 num2为除数 即num1/num2 
    // 每次都截取num1前面的length2长度的数值就和num2进行相除比较，并将所得的余数替换掉刚刚截取num1的字符串 
    // 比如1234/13 
    // 先取12<13,则num1向后移动一位为123/13,值为9，余数为6，则将num1变为64，再用64去除13，值为4，余数12，用12代替num1，即12/13，不够再补0，即120/13 
    // 依次下去 
    // 比较两个字符串的大小 
    boolean num1mtnum2(String num1, String num2) {
        boolean num1mtnum2 = false;
        if (num1.length() < num2.length()) {
            num1mtnum2 = false;
        }
        if (num1.length() == num2.length()) {
            if (num1.compareTo(num2) >= 0) {
                num1mtnum2 = true;
            }
            if (num1.compareTo(num2) < 0) {
                num1mtnum2 = false;
            }
        }
        if (num1.length() > num2.length()) {
            num1mtnum2 = true;
        }
        return num1mtnum2;
    }
    // 删除字符串前面的0 
    String slip0(String num) {
        while (num.length() > 1 && num.charAt(0) == '0') {
            num = num.substring(1);
        }
        return num;
    }
    String[] div(String num1, String num2)
    {
        
        
        String[] strResult = new String[2];
        
        int count = 0; // 小数点后的位数 
        
        // int length1 = num1.length();//被除数的长度 
        int length2 = num2.length();// 除数的长度 
        
        
        String result = "0";// 保存两数相除以后的商 
        String yushu = "0";// 保存余数，余数为0，表示刚好整除 
        
        String cut_num1 = "";// 保存用来截取num1的部分值 
        
        boolean num1mtnum2 = num1mtnum2(num1, num2);
        
        //如果当前的num1<num2那么就不进入while 循环 
        while(num1mtnum2)// 如果当前num1的长度不为0，并且小数点后的位数不足10位，则继续循环,求值 
        {
            int move = 1;// 用于保存一位一位的向后移动的参数 
            
            
            if(num1.length() < length2)// 如果当前num1长度小于num2的长度，则表明num1不能再去整除num2了，余数即为num1 
            {
                
//              System.out.println("num1.length()<length2 num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                
                
                
                if(yushu.equals("0"))// 如果余数是0，表示上一轮是整除，而此时的num1又小于num2那么在result后面补上num1长度的0 
                {
                    
//                  System.out.println("yushu.equals(0)"); 
                    
                    for(int i = 1; i <= num1.length();i++)
                    {
                        result = result + "0";
                    }
                    
//                  System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                }
                
                else// 否则补上 num1.length（）- yushu.length()个数的0 
                {
                    
                    
//                  System.out.println("yushu.!!!!!!equals(0)"); 
                    
                    for(int i = 1; i <= num1.length() - yushu.length(); i ++)
                    {
                        result = result + "0";
                    }
                    
//                  System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                }
                
                
                num1mtnum2 = false;
                yushu = num1;
                
                
                slip0(yushu);
                continue;
            }// end if(num1.length() < length2) 
            
            if(num1.length() == length2)// 当长度相等的时候，有3种情况：1num1>num2 num1=num2 
                                        // num1<num2 长度相同的时候可以用compareTo来比较大小 
            {
                
//              System.out.println("num1.length()==length2 num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                
                if(num1.compareTo(num2) < 0 )// num1<num2 
                {
                    
//                  System.out.println("num1.compareTo(num2) < 0"); 
                    
                    
                    if(yushu.equals("0"))// 如果余数是0，表示上一轮是整除，而此时的num1又小于num2那么在result后面补上num1长度的0 
                    {
                        
//                      System.out.println("yushu==0"); 
                        
                        for(int i = 1; i <= num1.length();i++)
                        {
                            result = result + "0";
                        }
                        
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    else// 否则补上 num1.length（）- yushu.length()个数的0 
                    {
                        
//                      System.out.println("yushu!=0"); 
                        for(int i = 1; i <= num1.length() - yushu.length(); i ++)
                        {
                            result = result + "0";
                        }
                        
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    num1mtnum2 = false;
                    yushu = num1;
                    
                    slip0(yushu);
                    continue;
                }// end if(num1.compareTo(num2) < 0 ) 
                
                
                if(num1.compareTo(num2) >= 0)// num1>num2 
                {
//                  System.out.println("num1.compareTo(num2) >= 0 "); 
                    
                    if(yushu.equals("0"))// 如果余数是0，表示上一轮是整除，而此时的num1大于num2那么在result后面补上num1长度-1个的0 
                    {
//                      System.out.println("yushu==0"); 
                        for(int i = 1; i < num1.length();i++)
                        {
                            result = result + "0";
                        }
                        
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    else// 否则补上 num1.length（）- yushu.length() - 1个的0 
                    {
//                      System.out.println("yushu!=0"); 
                        for(int i = 1; i < num1.length() - yushu.length(); i ++)
                        {
                            result = result + "0";
                        }
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    
                    
                    for(int i = 1 ; i <= 9; i++)
                    {
                        if(sub(num1,mult(num2,""+i)).charAt(0) == '0')
                        {// 刚好整除 num1-num2*i = 0 
                            
//                          System.out.println("num1-num2*i=0"); 
                            
                            yushu = "0";
                            result = result + i;
                            num1 = "";
                            num1mtnum2 = false;
                            
//                          System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                            
                            break;
                        }
                        
                        
                        
                        
                        if(sub(num1,mult(num2,""+i)).charAt(0) != '0' && sub(num1,mult(num2,""+i)).charAt(0) != '-' && sub(num1,mult(num2,""+i+1)).charAt(0) == '-')
                        {// 如果num1-num2*i > 0 num1-num2*(i+1)<0 
                            
//                          System.out.println("num1-num2*i>0 num1-num2*(i+1)<0"); 
                            
                            yushu = sub(cut_num1,mult(num2,""+i));
                            result = result + i;
                            num1 = yushu;
                            num1mtnum2 = false;
//                          System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                            break;
                        }// end if(sub(num1,mult(num2,""+i)).charAt(0) != '-' 
                            // && sub(num1,mult(num2,""+i+1)).charAt(0) == '-') 
                        
                    }// end for(int i = 1 ; i <= 9; i++) 
                    
                    
                    slip0(yushu);
                    continue;
                }// if(num1.compareTo(num2) >= 0) 
                
            }// end if(num1.length() == length2) 
            
            
            if(num1.length() > length2)
            {// num1肯定大于num2 
                
            
//              System.out.println("num1.length()>length2"); 
//              System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                
                
                cut_num1 = num1.substring(0,length2);
                
//              System.out.println("cut_num1:"+cut_num1); 
                
                // System.out.println("此时截取的值："+ cut_num1); 
                
                if(cut_num1.compareTo(num2) < 0)
                {// 截取的值小于num2 
                    
//                  System.out.println("cut_num1.compareTo(num2)<0"); 
                    
                    // System.out.println("截取的值小于num2"); 
                    
                    
                    if(yushu.equals("0"))// 如果余数是0，表示上一轮是整除，那么下次运算时，需在以前的商中补上截取长度-1个0 
                    {
                        
//                      System.out.println("yushu==0"); 
                        
                        for(int i = 1; i < cut_num1.length();i++)
                        {
                            result = result + "0";
                        }
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    else// 否则补上 num1.length（）- yushu.length()个数的0 
                    {
                        
//                      System.out.println("yushu != 0"); 
                        for(int i = 1; i < cut_num1.length() - yushu.length(); i ++)
                        {
                            result = result + "0";
                        }
                        
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    
                    
                    cut_num1 = num1.substring(0,length2+1);// 多截取一位，由于num1。length（） >length2所以不用考虑越界情况 
                    
                    
//                  System.out.println("再次截取的值："+ cut_num1); 
                    
                    if(!cut_num1.substring(0,cut_num1.length()-1).equals(yushu))//如果是直接在余数后面截取一位则不加0  否则商后面补一个0，至于商中没有值的情况，最后再作删除商前面值得操作 
                        result = result + "0";
                    
//                  System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    
                    
                    for(int i = 1 ; i <= 9; i++)
                    {   
                        
//                      System.out.println(i); 
                        
//                      System.out.println("sub(cut_num1,mult(num2,''+i)):" + sub(cut_num1,mult(num2,""+i))); 
//                      System.out.println("sub(cut_num1,mult(num2,''+i+1)):" + sub(cut_num1,mult(num2,""+(i+1)))); 
                        if(sub(cut_num1,mult(num2,""+i)).charAt(0) != '-' && sub(cut_num1,mult(num2,""+(i+1))).charAt(0) == '-')
                        {// 如果cut_num1-num2*i > 0 
                            // cut_num1-num2*(i+1)<0,此时不用考虑整除的情况 
                            
//                          System.out.println("cut_num1 - num2*i >0 && cut_num1-num2*(i+1)<0"); 
                            yushu = sub(cut_num1,mult(num2,""+i));
                            result = result + i;
                            num1 = yushu + num1.substring(cut_num1.length());// 此时的num1是余数+num1后面的数 
                            num1mtnum2 = num1mtnum2(num1, num2);// 比较下此时的num1和num2的大小 
                            
                            
//                          System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                            
                            break;
                        }// end if(sub(num1,mult(num2,""+i)).charAt(0) != '-' 
                            // && sub(num1,mult(num2,""+i+1)).charAt(0) == '-') 
                        
                    }// end for(int i = 1 ; i <= 9; i++) 
                
                    
                    slip0(yushu);
                    continue;// 执行下次循环 
                }
                
                if(cut_num1.compareTo(num2) >= 0)
                {// 截取的值>num2 
                    
                    
                    
//                  System.out.println("cut_num1.compareTo(num2) >= 0"); 
                    
//                  System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    
                    if(yushu.equals("0"))// 如果余数是0，表示上一轮是整除，那么下次运算时，需在以前的商中补上截取长度-1个0 
                    {
//                      System.out.println("yushu == 0"); 
                        
                        for(int i = 1; i < cut_num1.length();i++)
                        {
                            result = result + "0";
                        }
                        
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    else// 否则补上 num1.length（）- yushu.length()-1个的0 
                    {
                        
//                      System.out.println("yushu != 0"); 
                        
                        for(int i = 1; i < cut_num1.length() - yushu.length(); i ++)
                        {
                            result = result + "0";
                        }
//                      System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                    }
                    
                    
                    // System.out.println("截取的值大于num2"); 
                    
                    for(int i = 1 ; i <= 9; i++)
                    {
                        
                        // System.out.println("num2*i的结果：" + mult(num2,""+i)); 
                        
                        if(sub(cut_num1,mult(num2,""+i)).charAt(0) == '0')
                        {// 刚好整除 num1-num2*i = 0 
                            
//                          System.out.println("截取的值整除num2"); 
                            
                            yushu = "0";
                            result = result + i;
                            num1 =  num1.substring(cut_num1.length());
                            num1mtnum2 = num1mtnum2(num1,num2);
                            
//                          System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                            
                            break;
                        }
                        
                        
                        if(sub(cut_num1,mult(num2,""+i)).charAt(0) != '0' && sub(cut_num1,mult(num2,""+i)).charAt(0) != '-' && sub(cut_num1,mult(num2,""+(i+1))).charAt(0) == '-')
                        {// 如果cut_num1-num2*i > 0 cut_num1-num2*(i+1)<0 
                            
//                          System.out.println("截取的值不能整除num2"); 
                            
                            yushu = sub(cut_num1,mult(num2,""+i));
                            result = result + i;
                            num1 = yushu + num1.substring(cut_num1.length());
                            num1mtnum2 = num1mtnum2(num1,num2);
                            
//                          System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
                            
                            break;
                        }// end if(sub(num1,add(num2,""+i)).charAt(0) != '-' 
                            // && sub(num1,add(num2,""+i+1)).charAt(0) == '-') 
                        
                    }// end for(int i = 1 ; i <= 9; i++) 
                    
                    
                    slip0(yushu);
                    continue;
                }
                
            }// end if(num1.length() > length2) 
            
            
            
            
            
        
        }// end while 
        
        
        
        
        //由于当num1<num2的时候就不执行while循环，所以最后还得处理余下来的几位数字 
//          System.out.println("num1:" + num1 + ",result:"+result+ ",yushu:" + yushu); 
            
            
            
            if(yushu.equals("0"))// 如果余数是0，表示上一轮是整除，而此时的num1又小于num2那么在result后面补上num1长度的0 
            {
                
//              System.out.println("yushu.equals(0)"); 
                
                for(int i = 1; i <= num1.length();i++)
                {
                    result = result + "0";
                }
            }
            
            else// 否则补上 num1.length（）- yushu.length()个数的0 
            {
                
                
//              System.out.println("yushu.!!!!!!equals(0)"); 
                
                for(int i = 1; i <= num1.length() - yushu.length(); i ++)
                {
                    result = result + "0";
                }
            }
            
            //最后的余数就是当前的num1 
            yushu = num1;
        
        
            
        
        
        // 去除商result最前面的0,除非result值中只有一个0 
        while(result.length() > 1 && result.charAt(0) == '0')
        {
            result = result.substring(1);
        }
        
        
        // 将商和余数放在数组中返回 
        strResult[0] = result;
        strResult[1] = yushu;
        
        // System.out.println("商："+result); 
        // System.out.println("余数："+yushu); 
        
        
        return strResult;
    }
}