不管怎么输出都带一个  other char

#include <stdio.h>
int main(void)
{
    char ch;
    while(ch != '@',ch = getchar())
    {
        if(ch >= 'a' && ch <= 'z')
            printf("lowercase\n");
        else
            if(ch >= 'A' && ch <= 'Z')
                printf("uppercase\n");
            else
                if(ch >= '0' && ch <= '9')
                    printf("digital\n");
                else
                    printf("other char\n");
    }
    return 0;
}


j
lowercase
other char