#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/**
 * SOAL PRAKTIKUM PTI autoDECRYPTOR
 * file soal.enc harus pada direktori yang sama
 * inov@ynov.net
 **/

int main (int argc, char **argv)
{
  FILE * fp;
  FILE * fw;
  const char * fileInput = "soal.enc";
  const char * fileOutput = "praktikum.html";
  int geser;

  int i, j, k;
  fp = fopen (fileInput,"rb");

  char str[512][512];

  if (fp == NULL) perror ("Error! Tidak dapat membuka file!");
  else {
    char line [512];

    j = 0; // baris
    while (fgets (line, sizeof (line), fp) != NULL) {
      strcpy (str[j], line);
      j++;
    }
    fclose (fp);

    fp = fopen (fileInput,"rb");
    fw = fopen (fileOutput, "wb+");

    /** karena soal berupa HTML, maka dapat dipastikan awalan file adalah karakter '<' **/
    /* banyaknya pergeseran = selisih karakter awal dengan karakter '<' dalam ASCII */
    geser = '<'-str[0][0];

    for (i = 0; i < j; i++) {
      for (k = 0; k < (strlen (str[i])-1); k++) {
       printf ("%c", (str[i][k]+geser));
        fputc ((str[i][k]+geser), fw);
      }
      printf ("\n");
      fputc ('\n', fw);
    }
    fclose (fp);
    fclose (fw);
  }

  return 0;
}