/*
	A simple C program that demonstrates how to do simple I/O in
	C, using the scanf and printf functions.

	This program allows the user to make a copy of a file.  It
	prompts the user for the names of the original and duplicate
	files, and opens them.  It uses a loop to read individual
	characters from the first file and then writes them to the
	second.

	Author: Krishnan Pillaipakkamnatt
*/
  

/* Include standard headers. Vaguely similar to import statement
   in Java.*/
#include <stdio.h>

/* Program execution begins in the main function. */
int main()
{
   char next_char;    /* To hold input characters */
   int char_count;    /* Counts characters copied. */

   char in_name[256], /* char arrays are treated as strings. Here, */
	out_name[256];/* in_name is for the name of input file,  */
		      /* out_name is for the output file. */

   FILE *fin, *fout;  /* FILE pointers (handles) */


   /* Use printf to print messages to standard output: */
   printf("The super-D-duper file copying program.\n");
   printf("Please input source file name: ");

   /* Use scanf to input data from standard input. */
   scanf("%s", in_name);

   printf("Please input destination file name: ");
   scanf("%s", out_name);

   /* Attempt to open files. */

   fin = fopen(in_name, "r");
   if ( fin == NULL )
   {
      printf("Error. The file '%s' cannot be read. Exiting.\n");
      exit(1);
   }

   fout = fopen(out_name, "w");
   if ( fout == NULL )
   {
      printf("Error. The file '%s' cannot be written. Exiting.\n");
      exit(1);
   }

   char_count = 0;
   /* Use fscanf to read from input file. */
   while ( fscanf(fin, "%c", &next_char) != EOF ){
      /* Use fprint to print to output file. */
      fprintf(fout, "%c", next_char);
      char_count = char_count + 1;
   }

   /* We're done, close files. */
   fclose(fout);
   fclose(fin);

   printf("Copied %d chars.\n", char_count);
   /* Time to close shop. */
   exit(0);
}