数字转英文

/* 789 - seven hundred and eighty nine  */

/*思路：这人题思路很简单但是用c++程序实现起来比较繁琐，看了答案才知道 可以把 switch(){case}可以改成数组。哎。效率就是不行呀~！
如 char *a[]={"","one","two".........}*/
#include <iostream>
#include <string>
using namespace std;

char *Num_to_en(int num)
{
	switch(num)
	{
	case 1:return "one";
		break;
	case 2:return "tow";
		break;
	case 3:return "three";
		break;
	case 4:return "four";
		break;
	case 5:return "five";
		break;
	case 6:return "six";
		break;
	case 7: return "seven";
		break;
	case 8:return "eight";
		break;
	case 9:return "nine";
		break;
	default:
		cout<<"error"<<endl;
		break;
	}
}

char *ShiWei(int num)
{
	
	if(num<=20)
	{
		switch(num)
		{
		case 10:return "ten";
			break;
		case 11:return "elven";
			break;
		case 12:return "twelve";
			break;
		case 13:return "thirteen";
			break;
		case 14:return "fourteen";
			break;
		case 15:return "fifteen";
			break;
		case 16: return "sixteen";
			break;
		case 17:return "seventeen";
			break;
		case 18:return "eighteen";
			break;
		case 19:return "nineteen";
			break;
		case 20:return "twenty";
			break;
		}
	}
	else
		{
            int s=num/10;
        	int g=num%10;
			switch(s)
			{
			case 2:return "twenty";
				break;
			case 3:return "thirty";
				break;
			case 4:return "forty";
				break;
			case 5:return "fifty";
				break;
			case 6:return "sixty";
				break;
			case 7:return "seventy";
				break;
			case 8:return "eighty";
				break;
			case 9:return "ninety";
				break;
			case 0:return " ";

			}
		}

	
	
}

int main()
{
    cout<<"请输入一个三位整数"<<endl;
	int a1;
	cin>>a1;
	int bw=a1/100;
	int sw=a1%100;
	int sw1=a1%100/10;
	int gw=a1%10;
	if (sw1==0&&gw!=0) cout<<Num_to_en(bw)<<" hundred and "<<Num_to_en(gw)<<endl;
	else
		if(sw==0&&gw==0) cout<<Num_to_en(bw)<<" hundred"<<endl;
		else
	if(sw<21)cout<<Num_to_en(bw)<<" hundred and "<<ShiWei(sw)<<endl;
	else cout<<Num_to_en(bw)<<" hundred and "<<ShiWei(sw)<<" "<<Num_to_en(gw)<<endl;
	return 0;
}