//headers
#include <iostream>
#include <stdio.h>
#include <string>
//#include <time.h>
#include <ctime>    
#include <cstdlib>


//defines
#define RULE1  0   //denotes Rule 1 in MIU System
#define RULE2  1   //denotes Rule 2 in MIU System
#define RULE3  2   //denotes Rule 3 in MIU System
#define RULE4  3   //denotes Rule 4 in MIU System
#define TOTSTRING   5    //denotes the total number of strings generated

using namespace std;


//prototypes
void String_Generation();

int main(void)
{



/*print out useful info for MIU system*/
 cout<<"MIU System\n"<<endl;
 cout<<"Rule I:   If you have a string ending in I, you can add a U at the end."<<endl;
 cout<<"Rule II:  Suppose you have Mx.  Then you may add Mxx to your collection." <<endl;
 cout<<"Rule III: If III occurs in one of the strings in your collection you may"<<endl;
 cout<<"          make a new string with U in place of III."<<endl;
 cout<<"Rule IV:  If UU occurs inside one of your strings, you can drop it.\n"<<endl;

 

 //call string generation function
String_Generation();


 //keep command window up and running
 while(1)
 {
 }


 //exit main
	return 0;
}


/*
    generate next string from what is passed into function using 4 options
*/
void String_Generation()
{
  int rand_rule, num_strings, str_len; 
  string cur_string = "MI"; //init starting string
  string new_string, temp_string;
  char rule_two_char; 
  char * p_rule_two_char;

  p_rule_two_char = &rule_two_char;


  cout << "Starting string is: " << cur_string << endl;
   

  /* initialize random seed: */
  srand (time(NULL) );

 


//generate next string if needed
 for(num_strings=0; num_strings < TOTSTRING; num_strings++)
  {
	/* generate secret number: 0-3 */
    rand_rule = rand() % 4; 

	str_len = cur_string.length();
	
 //choose which rule to apply
  switch(rand_rule)
  {
  case RULE1: //Rule 1
	    if(cur_string[str_len-1]=='I')
		{
			new_string = cur_string;
			new_string.append("U");
			cout<<"RULE 1- Current String: "<< cur_string<<" New String: "<< new_string<<endl;
			cur_string = new_string;
		    break;
		}
  case RULE2: //Rule 2
	  if(cur_string[1]!= NULL)
	  {
		  new_string = cur_string; 
		  temp_string = new_string.substr(1);
          new_string.append(temp_string);
			
		cout<<"RULE 2- Current String: "<< cur_string<<" New String: "<< new_string<<endl;
		cur_string = new_string;
		break;
	  }
  case RULE3: //Rule 3
		 if(cur_string.find("III")!=string::npos)
	  {
		// let's replace the first III
	    new_string = cur_string;
        new_string.replace(new_string.find("III"),3,"U");
		cout<<"RULE 3- Current String: "<< cur_string<<" New String: "<< new_string<<endl;
		cur_string = new_string;
		break;
	  }
  case RULE4:
	   if(cur_string.find("UU")!=string::npos)
	  {
		// let's replace the first III
	    new_string = cur_string;
        new_string.replace(new_string.find("UU"),2,"");
		cout<<"RULE 4- Current String: "<< cur_string<<" New String: "<< new_string<<endl;
		cur_string = new_string;
		break;
	  }
	 
  default: 
	    //make sure operations can still be performed
	  if(cur_string.length() > 1)
		num_strings--;


	       break;

  }

  if(cur_string.compare("MU")==0)
	  num_strings = TOTSTRING;

  }//end if statement

}