Thread: Having problems manipulating two files - i'm a beginner.

Hi
I am trying to open two files in binary read mode and then XOR the contents of these files, character by chharacter, and store the results in a third file (by opening it in Binary write mode). Although i can open the two files but get a whole lot of garbage in the resultant file which is supposed to be having the XORed results. please help me.


Thanks in advance
Manu1

code:-

Code:

#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<stdlib.h>

void main(void)
{
  FILE *fptr, *fptr1, *fptr2, *fptr3, *fptr4;
  char plain[5000], ke[5000], cipher[5000];
  int i = 0, j=0, k=0, pt1[500], kt1[500];
  long int ch, ch1, ch2;
  clrscr();
  printf("\n ENTER PLAIN TEXT (PRESS ENTER TWICE TO EXIT):\n");
  fptr = fopen("ptxt.txt", "w");
  fflush(fptr);
  do {
      fputs(plain, fptr);
      fputs("\n", fptr);
      }
  while(strlen( gets(plain) ) > 0);
  fclose(fptr);
 // fflush(fptr);
  printf("\n ENTER KEY (PRESS ENTER TWICE TO EXIT):\n");
  fptr1 = fopen("ktxt.txt", "w");
  fflush(fptr1);
  do {
       fputs(ke, fptr1);
       fputs("\n", fptr1);
     }
  while(strlen( gets(ke) ) > 0);
  fclose(fptr1);
  //fflush(fptr1);

  fptr4 = fopen("ctxt.txt", "wb");
  fptr2 = fopen("ptxt.txt", "rb");
  fptr3 = fopen("ktxt.txt", "rb");

  fflush(fptr4);

  while (ch = getc(fptr2) != EOF)
  {
    ch1 = getc(fptr3) != EOF;
    cipher[i] = ch ^ ch1;
    i++;
    fwrite(cipher, sizeof(cipher), 1, fptr4);
   // i = j;
  }
/*  while (ch1 = getc(fptr3) != EOF )
  {
    kt1[k] = ch1;
    k++;
  }
    cipher[i] = ch ^ ch1;
   // i++;
   // putc(cipher, fptr4);
    i++;
  }*/
 /* for(k=0; k<j; k++)
  {
    putc(cipher[k], fptr4);
  }*/
  fclose(fptr2);
  fclose(fptr3);
  fclose(fptr4);
 // fflush(fptr4);

}

Hi Salem

Thanks a lot for your help.

I can create both files perfectly now, but im still getting the same type of abnormal data when i access the third file (which is supposed to have XORed data from both the files instead. Pl. help me with this. Following is my amended code:

Code:

#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<stdlib.h>

int main(void)
{
  FILE *fptr, *fptr1, *fptr2, *fptr3, *fptr4;
  char plain[5000], ke[5000], cipher[5000];
  int i = 0, j=0, k=0, pt1[500], kt1[500];
  long int ch, ch1, ch2;
  clrscr();
  printf("\n ENTER PLAIN TEXT (PRESS ENTER TWICE TO EXIT):\n");
  fptr = fopen("ptxt.txt", "w");
  
  while(fgets(plain, sizeof(plain),stdin)!= NULL)
  {
      if(plain[0]=='\n')
      break;
      fputs(plain, fptr);
      fputs("\n", fptr);
      }
 
  fclose(fptr);
 
  printf("\n ENTER KEY (PRESS ENTER TWICE TO EXIT):\n");
  fptr1 = fopen("ktxt.txt", "w");
  
  while(fgets(ke, sizeof(ke),stdin)!= NULL)
  {
      if(ke[0]=='\n')
      break;
      fputs(ke, fptr1);
       fputs("\n", fptr1);
  }
 
  fclose(fptr1);
  

  fptr4 = fopen("ctxt.txt", "wb");
  fptr2 = fopen("ptxt.txt", "rb");
  fptr3 = fopen("ktxt.txt", "rb");

  

  while(ch = fgets(plain, sizeof(plain),stdin)!= NULL)
  {
    
    if(ch1 = fgets(ke, sizeof(ke),stdin)!= NULL)
   { cipher[i] = ch ^ ch1;}
    i++;
    fwrite(cipher, sizeof(cipher), 1, fptr4);
  
  }

  fclose(fptr2);
  fclose(fptr3);
  fclose(fptr4);
 
}

I shall be very grateful for this help.
Regards

Manu

I have tried to improve the listing of the program so as to make it more simple to read. Your help will be highly appreciated.
Thanks & regards
Manu

Hey manu1, didn't you like the help that stober gave you at ProgramersHeaven with the question you posted
August 12, 2003 at 3:46:23 AM

It looked like by 8AM you had code working.

Now you post your original code here?

The original post, for those who are interested:
http://www.programmersheaven.com/c/M...ing=A0003F0001

And now you start a new thread?!?!?!!?

Keep using the same thread!
http://cboard.cprogramming.com/showt...threadid=43344