C语言经典例题-将输入的两位数转成英文

编写一个程序，要求用户输入一个两位数，然后显示该数的英文单词：

Enter a two-digit number: 45
You entered the number forty-five.
提示:把数分解为两个数字。用一个switch语句显示第一位数字对应的单词(“twenty”、"thirty”等),用第二个switch语句显示第二位数字对应的单词。不要忘记10~19需要特殊处理。
 

# include <stdio.h>

int main()
{
	int a1, a2;

	printf("Enter a two-digit number: ");
	scanf("%1d%1d", &a1, &a2);

	//先解决10-19 的数字
	if(a1 < 2){
		switch(a2){
		case 0: printf("You entered the number ten.\n"); break;
		case 1: printf("You entered the number eleven.\n"); break;
		case 2: printf("You entered the number twelve.\n"); break;
		case 3: printf("You entered the number thirteen.\n"); break;
		case 4: printf("You entered the number fourteen.\n"); break;
		case 5: printf("You entered the number fifteen.\n"); break;
		case 6: printf("You entered the number sixteen.\n"); break;
		case 7: printf("You entered the number seventeen.\n"); break;
		case 8: printf("You entered the number eighteen.\n"); break;
		case 9: printf("You entered the number nineteen.\n"); break;
		}
	}
	else{
		//十位数
		switch(a1){
		case 2: printf("You entered the number twenty"); break;
		case 3: printf("You entered the number thirty"); break;
		case 4: printf("You entered the number forty"); break;
		case 5: printf("You entered the number fifty"); break;
		case 6: printf("You entered the number sixty"); break;
		case 7: printf("You entered the number seventy"); break;
		case 8: printf("You entered the number eighty"); break;
		case 9: printf("You entered the number ninety"); break;
		}
		//个位数
		switch(a2){
		case 0: printf(".\n"); break;
		case 1: printf("-one.\n"); break;
		case 2: printf("-two.\n"); break;
		case 3: printf("-three.\n"); break;
		case 4: printf("-four.\n"); break;
		case 5: printf("-five.\n"); break;
		case 6: printf("-six.\n"); break;
		case 7: printf("-seven.\n"); break;
		case 8: printf("-eight.\n"); break;
		case 9: printf("-nine.\n"); break;
		}
	}

	return 0;

}