text: #include <stdio.h>
  #include <string.h>
  #define MAXLINE 1024
  
  void expand(char *s1, char *s2){
      char Alpha[26] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";    
      char alpha[26] = "abcdefghijklmnopqrstuvwxyz";
      char digits[10] = "0123456789";
  
      int i,j;
      i = 1;
      j = 0;    
      while(s1[i]){
      	if(s1[i] == '-'){
  	    if(s1[i-1] == 'a' && s1[i+1] == 'z'){
  	   	strcat(s2,alpha);
  		i += 2;
  		j += 26;
  	    }
  	    if(s1[i-1] == 'A' && s1[i+1] == 'Z'){
  	    	strcat(s2,Alpha);
  		i += 2;
  		j += 26;
  	    }
  	    if(s1[i-1] == '0' && s1[i+1] == '9'){
  	    	strcat(s2,digits);
  		i += 2;
  		j += 10;
  	    }
  	}
  	else{
  	    s2[j++] = s1[i++];
  	}
  	s2[j++] = s1[i++];	
      }
      s2[j] = '\0';
  }
  
  int main(){
      char result[MAXLINE];
      char *s1 = "a-z0-9A-Z---";
      expand(s1, result);
      printf("%s\n", result);
      return 0; 
  
  }
  