怎么样改才可以让这段代码可以输入（-600）然后输出(fu liu ling ling)

#include<stdio.h>int main(){ char ch; printf("enter a char:"); ch=getchar(); switch(ch){ case'-': printf("fu"); break; case'0': printf("ling"); break; case'1': printf("yi"); break; case'2': printf("er"); break; case'3': printf("san"); break; case'4': printf("si"); break; case'5': printf("wu"); break; case'6': printf("liu"); break; case'7': printf("qi"); break; case'8': printf("ba"); break; case'9': printf("jiu"); break; default: printf("dont know"); break; } return 0;}

#include <stdio.h>
int main()
{
    char ch;
    printf("enter a char:");
    while ((ch = getchar()) != '\n')
    {
        switch (ch)
        {
        case '-':
            printf("fu ");
            break;
        case '0':
            printf("ling ");
            break;
        case '1':
            printf("yi ");
            break;
        case '2':
            printf("er ");
            break;
        case '3':
            printf("san ");
            break;
        case '4':
            printf("si ");
            break;
        case '5':
            printf("wu ");
            break;
        case '6':
            printf("liu ");
            break;
        case '7':
            printf("qi ");
            break;
        case '8':
            printf("ba ");
            break;
        case '9':
            printf("jiu ");
            break;
        default:
            printf("dont know ");
            break;
        }
    }

    return 0;
}