Thread: Merging files....

Hello everyone ,
This function is supposed to merge 2 input files both contain sorted integers from the smallest to the largest into an output file which must be sorted too … everything works fine except when I have the same number in both input files i have it written twice in the out put file and this is wrong ...I tried to solve this problem but I couldn't… any ideas????!

Code:

void merge ( ifstream& infile_1 , ifstream& infile_2 , ofstream&outfile )
 
{

  int number_1 , number_2  ;
  
  infile_1 >> number_1 ;
  infile_2 >> number_2 ; 

  while ( (!infile_1.eof()) &&(!infile_2.eof()) )
 // while not end of file for both input files...
   
  { 
	  if ( number_1 > number_2)
	  { 
	      outfile << number_2 << endl ;
	      infile_2 >> number_2 ;
	  }	
     
  // ====================================//

      else if ( number_1 < number_2)
                 {
	      outfile << number_1 << endl ;
	      infile_1 >> number_1 ;
	  }

  // ====================================//

      if ( number_1 == number_2)
              {
                  outfile << number_1 << endl ;
	  infile_1 >> number_1 ;
              }
   }

  // ****************************************//

  while (!infile_1.eof()) 
 // while there are still numbers in the first input file...
    
   {  
       outfile << number_1 << endl ;
        infile_1 >> number_1 ;
   }
	 

  while (!infile_2.eof()) 
 // while there are still numbers in the second input file...
   
  {  
        outfile << number_2 << endl ;
        infile_2 >> number_2 ;
  }

  
}

Nope it didn't work....

Try this (I added in comments where i changed it)

Code:

...
while ( (!infile_1.eof()) &&(!infile_2.eof()) )
 // while not end of file for both input files...
   
  { 
	  if ( number_1 > number_2)
	  { 
	      outfile << number_2 << endl ;
	      infile_2 >> number_2 ;
	  }	
     
  // ====================================//

  else if ( number_1 < number_2)
  {
    outfile << number_1 << endl ;
    infile_1 >> number_1 ;
  }

  // ====================================//

  else if ( number_1 == number_2) // Yes, this should be an else.  If one of the above matches, then this could trigger also, which would produce errors.  You only want one of these three to trigger
  {
      outfile << number_1 << endl ;
    infile_1 >> number_1 ;
    infile_2 >> number_2 ;  // You need to get rid of BOTH numbers, because they are equal,  and you only want one of them.
  }
   
...

It worked thanx