U128803.阅读程序

#include  <ctype.h>
#include  <stdio.h>
void expand(char s1[], char s2[])
{
    int i, j, a, b, c;
    j = 0;
    for (i = 0; (c = s1[i]) != '\0'; i++)
        if(c == '-')
        {
            a = s1[i - 1]; b = s1[i + 1];
            if (isalpha(a) && isalpha(b) || isdigit(a) && isdigit(b))
            {
                j--;
                do
                    s2[j++] = a++;
                while (tolower(a) < tolower(s1[i + 1]));
            }
            else s2[j++] = c;
        } else s2[j++] = c;
    s2[j] = '\0';
}
int main()
{
    char s1[100], s2[300];
    gets(s1);
    expand(s1, s2);
    printf("%s\n", s2);
}

规定：输入的字符串只包含大小写字母，数字和“－”，且保证“－”不会出现在首位和末位。