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

/* Copy From Sourcefile To Destfile And return The Number */
/* Of Characters Copied; -1 For Errors */

int copy1( const char *destFile, const char *sourceFile )
{
  int charsCounted = 0;
  int ch;
  FILE *sfp, *dfp;

  if( strcmp( sourceFile, destFile ) == 0 )
  {
    printf( "Can not copy to self\n" );
    return -1;
  }

  if( ( sfp = fopen( sourceFile, "r" ) ) == NULL )
  {
    printf( "Can not open input file %s\n", sourceFile );
    return -1;
  }

  if( ( dfp = fopen( destFile, "w" ) ) == NULL )
  {
    printf( "Cannot open output file %s\n", destFile );
    fclose( sfp ); return -1;
  }

  while( ( ch = getc( sfp ) ) != EOF )
    if( putc( ch, dfp ) == EOF )
    {
      printf( "Unexpected error during write.\n" );
      break;
    }
    else
      charsCounted++;

  fclose( sfp );
  fclose( dfp );
  return charsCounted;
}

#define MAX_LINE_LEN 256
int copy2( const char *destFile, const char *sourceFile )
{
  int charsCounted = 0;
  char oneLine[ MAX_LINE_LEN + 2 ];
  FILE *sfp, *dfp;

  if( strcmp( sourceFile, destFile ) == 0 )
  {
    printf( "Can not copy to self\n" );
    return -1;
  }

  if( ( sfp = fopen( sourceFile, "r" ) ) == NULL )
  {
    printf( "Can not open input file %s\n", sourceFile );
    return -1;
  }

  if( ( dfp = fopen( destFile, "w" ) ) == NULL )
  {
    printf( "Cannot open output file %s\n", destFile );
    fclose( sfp ); return -1;
  }

  while( ( fgets( oneLine, MAX_LINE_LEN, sfp ) ) != NULL )
    if( fputs( oneLine, dfp ) < 0 )
    {
      printf( "Unexpected error during write.\n" );
      break;
    }
    else
      charsCounted += strlen( oneLine );

  fclose( sfp );
  fclose( dfp );
  return charsCounted;
}

int main( )
{
  int chars1 = 0;
  int chars2 = 0;

  chars1 = copy1( "out1.txt", "in.txt" );
  printf( "%d characters copied\n", chars1 );
  
  chars2 = copy2( "out2.txt", "in.txt" );
  printf( "%d characters copied\n", chars2 );
}