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)
知识点 字符串,循环,函数,指针,枚举,位运算,结构体,联合体,文件操作,递归 运行时间限制 10M 内存限制 128 输入 输入一个long型整数 输出 输出相应的英文写法 样例输入 2356 样例输出 two thousand three hundred and fifty six
#include <iostream> #include <string> using namespace std; string NUmberToEnglishString(long int number) { string s; if(number<0) { s="error"; return s; } if(number<20) { switch (number) { case 0: s="zero"; return s; case 1: s="one"; return s; case 2: s="two"; return s; case 3: s="three"; return s; case 4: s="four"; return s; case 5: s="five"; return s; case 6: s="six"; return s; case 7: s="seven"; return s; case 8: s="eight"; return s; case 9: s="nine"; return s; case 10: s="ten"; return s; case 11: s="eleven"; return s; case 12: s="twelve"; return s; case 13: s="thirteen"; return s; case 14: s="fourteen"; return s; case 15: s="fifteen"; return s; case 16: s="sixteen"; return s; case 17: s="seventeen"; return s; case 18: s="eighteen"; return s; case 19: s="nineteen"; return s; default: s="error"; return s; } } if(number<100) //21-99 { if (number % 10 == 0) //20,30,40,...90的输出 { switch (number) { case 20: s="twenty"; return s; case 30: s="thirty"; return s; case 40: s="forty"; return s; case 50: s="fifty"; return s; case 60: s="sixty"; return s; case 70: s="seventy"; return s; case 80: s="eighty"; return s; case 90: s="ninety"; return s; default: s="error"; return s; } } else { s=NUmberToEnglishString(number/10*10)+' '+NUmberToEnglishString(number%10); return s; } } if(number<1000) //100-999 { if(number%100==0) { s=NUmberToEnglishString(number/100)+" hundred"; return s; } else { s=NUmberToEnglishString(number/100)+" hundred and "+NUmberToEnglishString(number%100); return s; } } if(number<1000000) //1000-999999 百万以下 { if(number%1000==0) { s=NUmberToEnglishString(number/1000)+" thousand"; return s; } else { s=NUmberToEnglishString(number/1000)+" thousand "+NUmberToEnglishString(number%1000); return s; } } if(number<1000000000) //十亿以下 { if(number%1000000==0) { s=NUmberToEnglishString(number/1000000)+" million"; return s; } else { s=NUmberToEnglishString(number/1000000)+" million "+NUmberToEnglishString(number%1000000); return s; } } if (number<9999999999) //十亿到99亿 { if(number%1000000000==0) { s=NUmberToEnglishString(number/1000000000)+" billion"; return s; } else { s=NUmberToEnglishString(number/1000000000)+" billion "+NUmberToEnglishString(number%1000000000); return s; } } if (number>9999999999) { s="error"; return s; } } int main() { long int a; cin>>a; cout<<NUmberToEnglishString(a)<<endl; }