华为机试---学英语



题目描述

Jessi初学英语，为了快速读出一串数字，编写程序将数字转换成英文：

如22：twenty two，123：one hundred and twenty three。

 

说明：

数字为正整数，长度不超过十位，不考虑小数，转化结果为英文小写；

输出格式为twenty two；

非法数据请返回“error”；

关键字提示：and，billion，million，thousand，hundred。

 

方法原型：public static String parse(long num) 

 

 

 

输入描述:

输入一个long型整数

输出描述:

输出相应的英文写法

输入例子:

2356

输出例子:

two thousand three hundred and fifty six

import java.util.Scanner;

public class Main { public static void main(String[] args) {//  System.out.println(Long.MAX_VALUE);  //long max:9223372036854775807//  System.out.println("int :" + Integer.MAX_VALUE);  //int  max:2147483647  Scanner scan = new Scanner(System.in);  while (scan.hasNext()) {   String line = scan.nextLine();   //去除两端的空格操作   String str = line.trim();   //判断输入条件，如果过滤后输入的字符串长度为0，输出error   if (str.length() == 0) {    System.out.println("error");    continue;   }    //判断字符串是否是纯数字,true表示不是数字   boolean flag = true;   for (int i = 0; i < str.length(); i++) {    if (str.charAt(i) < '0' || str.charAt(i) > '9') {     System.out.println("error");     flag = false;     break;    }   }   //如果不是纯数字，继续下一次输入字符串   if (!flag) {    continue;   }   //字符串转化为长整型数字   long N = Long.parseLong(str);   String final_str = "";   //判断输入是否合法，正整数，长度不超过十位   if (isLegal(N)) {    final_str = parse(N);    System.out.println(final_str);   } else {    System.out.println("error");   }  }  scan.close(); } /**  * 判断输入是否合法，数字为正整数，长度不超过十位  * */ private static boolean isLegal(long n) {  boolean flag = false;  String limit_str = "9999999999";  long limit = Long.parseLong(limit_str);  if (n <= limit && n >= 0) {   flag = true;  }  return flag; } /**  * 将数字翻译成英文写法  * @param n是用户输入的长整型数字  * */ public static String parse(long n) {  String str = "";  // count_n代表数字的位数  int count_n = getDigits(n);  int temp_count_n = count_n;// 每次减一，寻找低的量级  int index_number = 0;// 保存某一位上的数字    for (int i = 1; i <= count_n; i++) {   // 获取某一位上的数字   index_number = getPositionInt(n, count_n, i);   str += matchEnglishKey(temp_count_n--, index_number , n , count_n , i);  }  return str; } /**  * 获得整数某一位上的数字  * @param n是用户输入的原始长整型数字  * @param count_n是数字n的总的长度  * @param index代表数字n中从左向右数第几个数字  * */ public static int getPositionInt(long n, int count_n, int index) {//  System.out.println("n:" + n + ",count_n:" + count_n + ",index:" + index);  //向前寻找的时候如果index越界，直接返回0，避免系统报错  if(index < 1) return 0;//  //向后寻找的时候如果index越界，直接返回0//  if(index > count_n) return 0;   int number = 0;  int count_time = count_n - index;// 统计寻找的次数  // System.out.println("需要计算的次数：" + count_time);  while (count_time > 0) {   n = n / 10;   count_time--;  }  number = (int) (n % 10);  return number; }

 /**  * 英文字母匹配,获得它的单位量级，billion,million,thousand,hundred  * @param n代表当前数字的总的位数，在数字总位数的基础上每次减一，根据位数可以判断出来单位量级  * @param index某位置上的数字，如果某位置上的数字为0需要特殊处理  * @param number代表用户输入的长整型数字  * @param count_n代表原始数字总的位数  * @param i位置的数字  * */ public static String matchEnglishKey(int n, int index , long number , int count_n , int i) {  String str = "";  int index_number_after = 0;  int index_number_after2 = 0;  int index_number_before = 0;  int index_number_before2 = 0;  //n当前数字总的位数  switch (n) {  //max_n 9999999999   表示  9 billion 999 million 999 thousand 999  case 10:   //如果n=10，则index一定非0   str += matchBitInt(index);   str += " billion";      break;  case 9:   //index某位置上的数字  为0时候，不输出   if(index == 0){    str += "";   }else{    //拼接100~999million语句    分为百位 十位 个位    //十位    index_number_after = getPositionInt(number, count_n, i + 1);//保存当前位后一位的数字    //个位    index_number_after2 = getPositionInt(number, count_n, i + 2);//保存当前位后面再后面一位的数字//    System.out.println("i:" + i +",after:" + index_number_after + ",after2:" + index_number_after2);    //百位后面两位都为0    if(index_number_after == 0 && index_number_after2 == 0 ){      if(count_n == n){      str += matchBitInt(index);      str += " hundred";     }else{      str += " ";      str += matchBitInt(index);      str += " hundred";     }         }else{     //后面两位如果有一位不为0都要添加and连接     // 在百位后面加and     if(count_n == n){      str += matchBitInt(index);      str += " hundred and ";     }else{      str += " ";      str += matchBitInt(index);      str += " hundred and ";     }         }   }      break;  case 8:    index_number_after = getPositionInt(number, count_n, i + 1);//保存当前位后一位的数字    //index某位置上的数字  为0时候，不输出   if(index == 0){        str += "";   }else{    //拼接10~99million语句    分为十位  个位  10~19 20~99    //如果当前位置上的数字等于1,10~19    if(index == 1){     //10~19     str += matchTenToNineteen(index , index_number_after);     str += "";    }else{     //>=20     if(index_number_after != 0){      //非整数21 ....,需要拼接      str += matchTenInt(index);      str += " ";     }else{      //整数20 30 40 ... 90       str += matchTenInt(index);     }    }       }    break;     case 7:   //拼接0~9million语句    index_number_before = getPositionInt(number, count_n, i - 1);//保存当前位前一位的数字   index_number_before2 = getPositionInt(number, count_n, i - 2);//保存当前位前两位的数字   if(index == 0){   //当前位置的字符为0    if(index_number_before >= 1){     //如果前一位大于等于1     str += " million";    }else{     //如果前一位等于0，看前两位     if(index_number_before2 == 0){      str += "";     }else{      //如果前两位不等于0      str += " million";     }         }       }else{   //当前位置的字符不等于0      //    System.out.println("index_number_before" + index_number_before);    //如果前面的数字等于1，代表10~19表示已经输出过了    if(index_number_before != 1){     //如果前面的数不等于1，并且当前位置的数字不等于0           str += matchBitInt(index);     str += " million";    }else{     str += " million";    }     }               break;  case 6:   if(index == 0){    str += "";   }else{    //拼接100~999thousand语句    分为百位 十位 个位    //十位    index_number_after = getPositionInt(number, count_n, i + 1);//保存当前位后一位的数字    //个位    index_number_after2 = getPositionInt(number, count_n, i + 2);//保存当前位后面再后面一位的数字//    System.out.println("i:" + i +",after:" + index_number_after + ",after2:" + index_number_after2);    //后面两位如果有有一位不为0都要添加and连接    if(index_number_after == 0 && index_number_after2 == 0){          //百位后面两位都为0     //如果数字本来就是6位     if(count_n == n){            str += matchBitInt(index);      str += " hundred";     }else{      str += " ";      str += matchBitInt(index);      str += " hundred";     }         }else{          // 在百位后面加and     if(count_n == n){      str += matchBitInt(index);      str += " hundred and ";     }else{      str += " ";      str += matchBitInt(index);      str += " hundred and ";     }       }   }      break;  case 5:      index_number_after = getPositionInt(number, count_n, i + 1);//保存当前位后一位的数字      if(index == 0){        str += "";   }else{    //如果当前位置上的数字等于1，,10~19    if(index == 1){     //10~19     str += matchTenToNineteen(index , index_number_after);     str += "";    }else{     //>=20     if(index_number_after != 0){      str += matchTenInt(index);      str += " ";     }else{      str += matchTenInt(index);     }    }       }    break;  case 4:   index_number_before = getPositionInt(number, count_n, i - 1);//保存当前位前一位的数字   index_number_before2 = getPositionInt(number, count_n, i - 2);//保存当前位前两位的数字   //前面有1个数字 21，1是当前位置的字符   if(index == 0){    //当前位置的字符为0    if(index_number_before >= 1){     //如果前一位大于等于1     str += " thousand";    }else{     //如果前一位等于0，看前两位     if(index_number_before2 == 0){      str += "";     }else{      //如果前两位不等于0      str += " thousand";     }         }       }else{   //当前位置的字符不等于0      //    System.out.println("index_number_before" + index_number_before);    //如果前面的数字等于1，代表10~19表示已经输出过了    if(index_number_before != 1){     //如果前面的数不等于1，并且当前位置的数字不等于0           str += matchBitInt(index);     str += " thousand";    }else{     str += " thousand";    }     }          break;  case 3:   index_number_after = getPositionInt(number, count_n, i + 1);//保存当前位后一位的数字   index_number_after2 = getPositionInt(number, count_n, i + 2);//保存当前位后面再后面一位的数字   if(index == 0){    str += "";   }else{    //    System.out.println("i:" + i +",after:" + index_number_after + ",after2:" + index_number_after2);    //后面两位如果有有一位不为0都要添加and连接    if(index_number_after == 0 && index_number_after2 != 0 || index_number_after != 0 && index_number_after2 == 0 || index_number_after != 0 && index_number_after2 != 0){          // 在百位后面加and     if(count_n == n){      str += matchBitInt(index);      str += " hundred and ";     }else{      str += " ";      str += matchBitInt(index);      str += " hundred and ";     }         }    if(index_number_after == 0 && index_number_after2 == 0 ){     //百位后面两位都为0     if(count_n == n){      str += matchBitInt(index);      str += " hundred";     }else{      str += " ";      str += matchBitInt(index);      str += " hundred";     }         }           }   break;  case 2:      index_number_after = getPositionInt(number, count_n, i + 1);//保存当前位后一位的数字    index_number_before = getPositionInt(number, count_n, i - 1);//保存当前位后一位的数字   if(index == 0){        str += "";   }else{    if(index == 1){     str += matchTenToNineteen(index , index_number_after);     str += "";    }else{     if(index_number_after != 0){      if(index_number_before == 0){       str += " ";       str += matchTenInt(index);       str += " ";      }else{       str += matchTenInt(index);       str += " ";      }           }else{      str += matchTenInt(index);     }    }       }       break;  case 1:             index_number_before = getPositionInt(number, count_n, i - 1);//保存当前位后一位的数字   //前面有1个数字 21，1是当前位置的字符   if(index == 0){        str += "";          }else{   //当前位置的字符不等于0,判断十位，百位的数字      //    System.out.println("index_number_before" + index_number_before);    //如果前面的数字等于1，代表10~19表示已经输出过了    if(index_number_before != 1){     //如果前面的数不等于1，并且当前位置的数字不等于0           str += matchBitInt(index);         }else{     str += "";    }     }          break;      default:   break;  }  return str; }

 /**  * 匹配个位数，1,2...  * @param n是个位上的数字  * */ public static String matchBitInt(int n) {  String str = "";  switch (n) {  case 9:   str = "nine";   break;  case 8:   str = "eight";   break;  case 7:   str = "seven";   break;  case 6:   str = "six";   break;  case 5:   str = "five";   break;  case 4:   str = "four";   break;  case 3:   str = "three";   break;  case 2:   str = "two";   break;  case 1:   str = "one";   break;  default:   str = "";   break;  }  return str; }

 /**  * 匹配10~19这十个数字  * */ public static String matchTenToNineteen(int shiWei , int geWei){  String str = "";  int n = shiWei * 10 + geWei;  switch(n){  case 10:   str += "ten";   break;  case 11:   str += "eleven";   break;  case 12:   str += "twelve";   break;  case 13:   str += "thirteen";   break;  case 14:   str += "fourteen";   break;  case 15:   str += "fifteen";   break;  case 16:   str += "sixteen";   break;  case 17:   str += "seventeen";   break;  case 18:   str += "eighteen";   break;  case 19:   str += "nineteen";   break;  default:   str += "";   break;  }  return str; } /**  * 匹配十位数，20,30...  * */ public static String matchTenInt(int n) {  String str = "";  switch (n) {  case 9:   str = "ninety";   break;  case 8:   str = "eighty";   break;  case 7:   str = "seventy";   break;  case 6:   str = "sixty";   break;  case 5:   str = "fifty";   break;  case 4:   str = "forty";   break;  case 3:   str = "thirty";   break;  case 2:   str = "twenty";   break;  default:   str = "";   break;  }  return str; }

 /**  * 获取输入整数的位数  * */ private static int getDigits(long n) {  int count = 0;  while (n != 0) {   count++;   n = n / 10;  }  // System.out.println(count);  return count; }}