程序代码：

#include <stdio.h>

int main(void)
{
    int ten_digit, sigle_digit;

    printf("Enter a two digit number: ");
    scanf("%d%d", &ten_digit, &sigle_digit);

    if (ten_digit == 1)
    {
        switch (sigle_digit)
        {
            case 0:
                printf("You enter the number ten");
                break;
            case 1:
                printf("You enter the number eleven");
                break;
            case 2:
                printf("You enter the number twelve");
                break;
            case 3:
                printf("You enter the number thirdteen");
                break;
            case 4:
                printf("You enter the number forteen");
                break;
            case 5:
                printf("You enter the number fifteen");
                break;
            case 6:
                printf("You enter the number sixteen");
                break;
            case 7:
                printf("You enter the number seventeen");
                break;
            case 8:
                printf("You enter the number eighteen");
                break;
            case 9:
                printf("You enter the number nineteen");
                break;
            default:
                break;
        }
    }

    else
    {
        switch (ten_digit)
        {
            case 2:
                printf("You enter the number twenty-");
                break;
            case 3:
                printf("You enter the number thirty-");
                break;
            case 4:
                printf("You enter the number forty-");
                break;
            case 5:
                printf("You enter the number fifty-");
                break;
            case 6:
                printf("You enter the number sixty-");
                break;
            case 7:
                printf("You enter the number seventy-");
                break;
            case 8:
                printf("You enter the number eighty-");
                break;
            case 9:
                printf("You enter the number nighty-");
                break;
            default:
                break;
        }

        switch (sigle_digit)
        {
            case 1:
                printf("You enter the number one");
                break;
            case 2:
                printf("You enter the number two");
                break;
            case 3:
                printf("You enter the number three");
                break;
            case 4:
                printf("You enter the number four");
                break;
            case 5:
                printf("You enter the number five");
                break;
            case 6:
                printf("You enter the number six");
                break;
            case 7:
                printf("You enter the number seven");
                break;
            case 8:
                printf("You enter the number eight");
                break;
            case 9:
                printf("You enter the number night");
                break;
            default:
                break;
        }
    }

    return 0;
}

程序代码：

#include <stdio.h>

int main(void)
{
    int ten_digit, sigle_digit,num;
    char name_1[10][20]={"one","two","three","four","five","six","seven","eight","night"} ;
    char name_2[10][20]={"ten","eleven","twelve","thirdteen","forteen","fifteen","sixteen","seventeen","eighteen","nineteen"};
    char name_3[10][20]={"twenty","thirty","forty","fifty","sixty","seventy","eighty","nighty"};
    
    for(printf("Enter a digit number: ");scanf("%d", &num)!=1;
        scanf("%*[^\n]"), printf("%s","Exception: data format , try again: "));
    ten_digit=num/10;
    sigle_digit=num%10;
    switch(ten_digit)
    {
        case 0:
            printf("You enter the number %s",name_1[sigle_digit-1]);
            break;
        case 1:
            printf("You enter the number %s",name_2[sigle_digit]);
            break;
        default:
            switch(sigle_digit)
            {
                case 0:
                    printf("You enter the number %s",name_3[ten_digit-2]);
                    break;
                default:
                    printf("You enter the number %s-%s",name_3[ten_digit-2],name_1[sigle_digit-1]);
            }
    }
    return 0;
}