TCPL学习笔记：编写expand(s1, s2),将字符串s1中类似于a-z一类的速记符号在s2中扩充完整。可以处理大小写及字符，以及a-b-c， a-z0-9以及-a-z等多种情况。

话不多说，看代码：

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
    char s1[180] = "a-z0-9hahah-a-z-s-d";
    char s2[180];
    expand(s1, s2);
    printf("Now the s2 is : %s", s2);
    return 0;
}

void expand(char * s1, char * s2)
{
    int i = 0, j = 0, c;
    while((c = s1[i++]) != ‘\0‘)
    if(s1[i] == ‘-‘ &&  s1[i + 1] > c){
    i++;
    while(c < s1[i])
    s2[j++] = c++;
    }else
    s2[j++] = c;
    s2[j] = ‘\0‘;
}