careercup-中等难度 17.7

17.7 给定一个整数，打印该整数的英文描述（例如“One Thousand，Two Hundred Thirty Four”）。

解法：

举个例子，在转换19 323 984时，我们可以考虑分段处理，没三位转换一次，并在适当的地方插入“thousand”（千）和“million”（百万）。也即，

convert（19 323 984）=convert（19）+ “ million ”+convert（323）+“ thousand ”+convert（984）；

 

C++实现代码：

#include<iostream>

#include<string>

using namespace std;



string digits[10]={"One","Two","Three","Four","Five","Six","Seven","Eight","Nine"};



string teens[10]={"Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen"};



string tens[10]={"Ten","Twenty","Thirty","Forty","Fifty","Sixty","Seventy","Eighty","Ninety"};



string big[10]={"","Thousand","Million"};



string numToString100(int number)

{

    string str;

    if(number>100)

    {

        str+=digits[number/100-1]+" Hundred ";

    }

    number%=100;

    if(number>=11&&number<=19)

    {

        return str+teens[number-11]+" ";

    }

    else if(number==10||number>=20)

    {

        str+=tens[number/10-1]+" ";

        number%=10;

    }

    if(number>=1&&number<=9)

    {

        str+=digits[number-1]+" ";

    }

    return str;

}

string  numToString(int number)

{

    if(number==0)

    {

        return "Zero";

    }

    else if(number<0)

    {

        return " Negative "+numToString(-1*number);

    }

    int count=0;

    string str=" ";

    while(number>0)

    {

        if(number%1000)

        {

            str=numToString100(number%1000)+big[count]+" "+str;

        }

        number/=1000;

        count++;

    }

    return str;

}



int main()

{

    cout<<numToString(1109);

}