// Name 
// CS201 HW5
// Problem 1

#include <iostream> 
#include <cmath>

using namespace std;

// triangle function prototype
void triangle (int s1, int s2, int s3, double& area, double& perimeter);

int main()
{
    double area=0, perimeter=0; 
    int a, b, c;

    cout << "Enter the lengths of each side for a triangle: \n";
    cin >> a >> b >> c;

    if (a+b>c && a+c>b && b+c>a) { //check for a reasonable combination of a, b, c
 
       triangle(a, b, c, area, perimeter);
	
       cout << " \nThe perimeter of the triangle is " <<perimeter << ", \n"
	    <<"and the area of the triangle is " << area << ".\n" ;
	
    }
    else 
       cout << " \nA triange cann't be constructed with the sides " 
            << a << ", " << b << ", " << c << ".\n";

    return 0;
}

void triangle (int a, int b, int c, double& area, double& perimeter)
{
   double s;  
  
   perimeter = a + b + c;
   s = perimeter/2;
   area = sqrt(s*(s-a)*(s-b)*(s-c));
}

/*
Enter the lengths of each side for a triangle:
3 4 5

The perimeter of the triangle is 12,
and the area of the triangle is 6.
Press any key to continue
*/

/*
Enter the lengths of each side for a triangle:
1 3 10

A triange cann't be constructed with the sides 1, 3, 10.
Press any key to continue
*/


// Name
// CS201 HW5
// Problem 2

#include <iostream>
#include <istream>
#include <fstream>
#include <cstdlib>
using namespace std;

//creat the initial advice, you may use any text editor to do this
void initial_advice();

//function to print out the previous advice
void my_advice();

//function to ask for your advice
void your_advice();

int main()
{	
    
   initial_advice();  // generate advice.txt file include the very first advice
	              //if you have advice.txt already, you don't need to do this 

   char repeat = 'y';
	
   do
   {
      my_advice();
      your_advice();

      cout << "Would you like to run this program again? (y/n) \n";
      cin >> repeat;
   } while (repeat=='y' || repeat=='Y');

   return 0;
}

void initial_advice()
{  
   ofstream out_stream;

   out_stream.open("advice.txt");
   if (out_stream.fail())
   {
      cout << "Output file opening failed.\n";
      exit(1);
   }
	
   out_stream <<"Please put your name and problem # in your program\n";
   out_stream.close();
}

void my_advice()
{
   ifstream in_stream;

   in_stream.open("advice.txt");

   if (in_stream.fail())
   {
      cout << "Input file opening failed.\n";
      exit(1);
   }
	
   cout << "The following is my advice to you:\n";
   char next_symbol;
   in_stream.get(next_symbol);
   while (!in_stream.eof())
   {
      cout << next_symbol;
      in_stream.get(next_symbol);
   }

   in_stream.close();

   cout << endl;
}

void your_advice()
{
   ofstream out_stream;

   out_stream.open("advice.txt");
   if (out_stream.fail())
   {
      cout << "Output file opening failed.\n";
      exit(1);
   }
	
   char next_symbol;
   cout << "Enter some new advice and press enter twice when done:\n";

   int return_check = 0; // a flag for meeting two consecutive \n s
	
   do
   {
      cin.get(next_symbol);

      if (next_symbol == '\n')    
      {
	 out_stream << next_symbol;
	 cin.get(next_symbol);
	 if (next_symbol == '\n')  // If two consecutive \n, it ends
	    return_check = 1;
	 else
	    out_stream << next_symbol;
      }
      else
	 out_stream << next_symbol;
   } while (return_check != 1);

   out_stream.close();
}


/*
The following is my advice to you:
Please put your name and problem # in your program

Enter some new advice and press enter twice when done:
Please keep your program as simple as possible

Would you like to run this program again? (y/n)
y
The following is my advice to you:
Please keep your program as simple as possible

Enter some new advice and press enter twice when done:
Please do exactly what the problem ask you to do, and
use as many functions as possible
in your programs

Would you like to run this program again? (y/n)
n
Press any key to continue
*/


// Name
// CS201 HW5
// Problem 3

#include <cstdlib>
#include <iostream>
#include <fstream>
using namespace std;

// function prototype
void order_list(ifstream& file1, ifstream& file2, ofstream& output);
void checkfile(char file[16]);

int main()
{
   char retry='y';

   do{	
       // assume file namce has 16 or less charaters
       char file_one[16], file_two[16], file_three[16]; 
	
       ifstream in_stream1, in_stream2;
       ofstream out_stream;

       // enter input file one
       cout << "Enter input file one:\n";
       cin >> file_one;
       in_stream1.open(file_one, ios::in|ios::binary );
       checkfile(file_one);
	
       // enter input file two
       cout << "Enter input file two:\n";
       cin >> file_two;
       in_stream2.open(file_two, ios::in|ios::binary );
       checkfile(file_two);
	
 	// enter output file name
	cout << "Enter output file:\n";
	cin >> file_three;
	out_stream.open(file_three);
	checkfile(file_three);

	//sort the numbers from two files and output them to the third file
	order_list (in_stream1, in_stream2, out_stream);

	// run program again? */
	
	cout << endl << "Again? (y/n)"; 
	cin >> retry;
    } while(retry=='y'||retry=='Y');	

    return 0;		
}

// check file to see if it openned
void checkfile(char file[16])
{	
   ifstream stream;
   stream.open(file);
   if (stream.fail())
   {
      cout << "Opening the file '" << file <<"' failed!\n";
      exit(1);
   }
   stream.close();
} 

void order_list(ifstream& in_stream1, ifstream& in_stream2, ofstream& output)
{	
     int number_one;
     int number_two;

     // get two nubmers from the two files
     in_stream1 >> number_one;
     in_stream2 >> number_two;
	
     // if the two files both donot come to EOF, save the smaller (<=) number from one file 
     // and get another number from that file for next comparsion.
     while (!in_stream1.eof() && !in_stream2.eof())
     {
 	if ( number_one <= number_two )
 	{
 	    output << number_one << "\n";
  	    in_stream1 >> number_one; 
  	}
 	else 
 	{
 	     output << number_two << "\n";
 	     in_stream2 >> number_two;
 	}
      }

      // if come to the end of one file, all the rest in the 
      // other file must be larger and in order

      if ( !in_stream1.eof() )      // in_stream2 come to EOF  
         while (!in_stream1.eof())
         {
  	    output << number_one << "\n";	 	
	    in_stream1 >> number_one;
         }
       else                         // in_stream1 come to EOF
          while (!in_stream2.eof())
	  {
	     output << number_two << "\n";
	     in_stream2 >> number_two;

	  }
}

/*
Enter input file one:
input1.dat
Enter input file two:
input2.dat
Enter output file:
output1.dat

Again? (y/n)y
Enter input file one:
input1.dat
Enter input file two:
input3.dat
Enter output file:
output2.dat

Again? (y/n)y
Enter input file one:
input2.dat
Enter input file two:
input3.dat
Enter output file:
output3.dat

Again? (y/n)n
Press any key to continue

*/



/****output1.dat*******
1
2
10
11
12
13
14
*/

/*****output2.dat******
1
5
5
11
13
35
35
*/

/*****output3.dat******
2
5
5
10
12
14
35
35
*/