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Oct 14th, 2007

Parallel Array/Reading In From A File

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I have a file that is representing an image, here's the puddle.img file:
10 22
2222888222882222228882
2222888222882222228882
3333333333333333333333
1111111111111111111111
1111144444111111111111
1111444444411551111111
1114643434345551111111
1111333333311551111111
1111133333111111115114
1111111111111111115543

The first two numbers are the size of the image, rows and then columns. Then I have to pull in the image, and before the user sees it, it is rendered, such as a 0 = a space, 1 = -, 2 is =, 3 is a O and so forth. So they'll see this after they enter the name of the image file:

====WWW===WW======WWW=
====WW===WWWW=====WWW=
OOOOOOOOOOOOOOOOOOOOOOOO
-------------------------------------------
-----ZZZZZ------------------------------
----ZZZZZZZ--XX-----------------------
---ZBZOZOZOXXX----------------------
----OOOOOOO--XX---------------------
-----OOOOO------------------------X--Z
-------------------------------------XXZO

Basically 1-9 each mean something else when rendered before outputting to the screen.

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;
 
string filename;
int rows;
int cols;
int k = 0;
int m = 0;
string row;
const int ROW_SIZE = 40;
const int COL_SIZE = 70;
int image [ROW_SIZE][COL_SIZE];
 
int main()
{
  ifstream inFile;
  cout << "Enter image file name:" << endl;
  getline(cin, filename);
  inFile.open(filename.c_str());
 
 
 
return 0;
}
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;

string filename;
int rows;
int cols;
int k = 0;
int m = 0;
string row;
const int ROW_SIZE = 40;
const int COL_SIZE = 70;
int image [ROW_SIZE][COL_SIZE];

int main()
{
  ifstream inFile;
  cout << "Enter image file name:" << endl;
  getline(cin, filename);
  inFile.open(filename.c_str());



return 0;
}

I tried messing with a getline to get the row and column number, but getline can't be used with integers, then if I use a cin I think it gets stuck on whitespace and just sits there.

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DemonSpeeding

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Oct 14th, 2007

Re: Parallel Array/Reading In From A File

> ... but getline can't be used with integers ...
it is easier to process each element in your image as a char rather than an int. eg.

c++ Syntax (Toggle Plain Text)
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <cassert>
#include <iterator>
using namespace std;
 
struct replace_chars
{
  string operator() ( const string& str ) const
  {
    string result = str ;
    for( size_t i=0 ; i<result.size() ; ++i )
    {
      switch( result[i] )
      {
        case '0' : result[i] = ' ' ; break ;
        case '1' : result[i] = '-' ; break ;
        case '2' : result[i] = '=' ; break ;
        case '3' : result[i] = 'O' ; break ;
        // etc
      }
    }
    return result ;
 }
};
 
int main()
{
  string filename ;
  getline( cin, filename ) ;
  ifstream file( filename.c_str() ) ;
  size_t rows, cols ;
  file >> rows >> cols >> ws ; // skip over white spaces
  assert( rows>0 && cols>0 ) ;
  vector< string > image ;
  const string digits = "0123456789" ;
  string line ;
  while( getline( file, line ) && ( image.size() < rows ) )
  {
    assert( line.size() == cols ) ;
    assert( line.find_first_not_of(digits) == string::npos ) ;
    image.push_back( line ) ;
  }
  assert( image.size() == rows ) ;
  transform( image.begin(), image.end(),
             ostream_iterator<string>(cout,"\n"),
             replace_chars() ) ;
}
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <cassert>
#include <iterator>
using namespace std;

struct replace_chars
{
  string operator() ( const string& str ) const
  {
    string result = str ;
    for( size_t i=0 ; i<result.size() ; ++i )
    {
      switch( result[i] )
      {
        case '0' : result[i] = ' ' ; break ;
        case '1' : result[i] = '-' ; break ;
        case '2' : result[i] = '=' ; break ;
        case '3' : result[i] = 'O' ; break ;
        // etc
      }
    }
    return result ;
 }
};

int main()
{
  string filename ;
  getline( cin, filename ) ;
  ifstream file( filename.c_str() ) ;
  size_t rows, cols ;
  file >> rows >> cols >> ws ; // skip over white spaces
  assert( rows>0 && cols>0 ) ;
  vector< string > image ;
  const string digits = "0123456789" ;
  string line ;
  while( getline( file, line ) && ( image.size() < rows ) )
  {
    assert( line.size() == cols ) ;
    assert( line.find_first_not_of(digits) == string::npos ) ;
    image.push_back( line ) ;
  }
  assert( image.size() == rows ) ;
  transform( image.begin(), image.end(),
             ostream_iterator<string>(cout,"\n"),
             replace_chars() ) ;
}

Last edited by vijayan121; Oct 14th, 2007 at 9:49 pm.

vijayan121

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Posting Virtuoso

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Oct 14th, 2007

Re: Parallel Array/Reading In From A File

You can use >> operator to get the row/column values as ints, then read the data as individual chars

C++ Syntax (Toggle Plain Text)
inFile >> rows >> columns;
infile.ignore( 10, '\n');  //ignores up to 10 characters, or until newline
//or
infile.ws( );  //eats up the whitespace
inFile >> rows >> columns;
infile.ignore( 10, '\n');  //ignores up to 10 characters, or until newline
//or
infile.ws( );  //eats up the whitespace

Then begin to read your data ( as characters, as vijayan suggests)

C++ Syntax (Toggle Plain Text)
inFile >> image[r][c];  //inside a loop that correctly corresponds to the row and column values you read in.
inFile >> image[r][c];  //inside a loop that correctly corresponds to the row and column values you read in.

vmanes

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Oct 15th, 2007

Re: Parallel Array/Reading In From A File

Thanks for the help so far, I believe I'm now ignoring the whitespace or that first line when I'm going to try and read the image. I was told something about using nested for loops to draw in the image, you'll see it in the code I have now, I'm still messing around with it trying to get it to work. If I had used structs before or had any familiarity with them I would've gone that route, but I've never used them before. I'm trying to solve this particular problem through parallel arrays.

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;
 
string filename;
int rows;
int cols;
int k = 0;
int m = 0;
string bum;
string row;
const int ROW_SIZE = 40;
const int COL_SIZE = 70;
int image [ROW_SIZE][COL_SIZE];
int main()
{
  ifstream inFile;
  cout << "Enter image file name:" << endl;
  getline(cin, filename);
  inFile.open(filename.c_str());
  inFile >> rows >> cols;
  inFile.ignore( 10, '\n');
  inFile >> image[k][m];
  while (inFile){
  for (k =0; k < rows; k++)
      for (m =0; m < cols; m++)
  inFile >> image[k][m];
  }
  cout << image[2][3];
return 0;
}
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;

string filename;
int rows;
int cols;
int k = 0;
int m = 0;
string bum;
string row;
const int ROW_SIZE = 40;
const int COL_SIZE = 70;
int image [ROW_SIZE][COL_SIZE];
int main()
{
  ifstream inFile;
  cout << "Enter image file name:" << endl;
  getline(cin, filename);
  inFile.open(filename.c_str());
  inFile >> rows >> cols;
  inFile.ignore( 10, '\n');
  inFile >> image[k][m];
  while (inFile){
  for (k =0; k < rows; k++)
      for (m =0; m < cols; m++)
  inFile >> image[k][m];
  }
  cout << image[2][3];
return 0;
}

I can tell at the moment what I have isn't doing the trick, if I try to cout just a certain piece of the image, even before converting it to whatever characters it should come out as, it always couts a 0. So what I have isn't doing the trick.

DemonSpeeding

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Oct 15th, 2007

Re: Parallel Array/Reading In From A File

>> int image [ROW_SIZE][COL_SIZE];
OK. You want to display the image as characters ... do you need to keep it in memory? If you do you can either change the type of the image to a character array. It'll read in all the numbers as single characters. Then, once it's all read in, you can convert a '0' to a '-' or whatever, hece using the same variable.
Alternatively you could just create a second array of the same size...

It might be worth dynamically allocating enough memory for the image at runtime ... You familiar with new/delete?

twomers

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Oct 15th, 2007

Re: Parallel Array/Reading In From A File

I do need to keep it in memory because after I output what it looks like after being rendered, you know with the whole 0= 1=, stuff, the user can then brighten or darken the image, which will increment all the integers in the image +1 or -1 depending if they chose to brighten or darken it. I changed my array to char like you said, and now it is working, when I cout a specific cell the correct integer actually comes out. How can I get the entire image posted to the screen? More for loops?

DemonSpeeding

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Oct 15th, 2007

Re: Parallel Array/Reading In From A File

c Syntax (Toggle Plain Text)
  for (k =0; k < rows; k++)
      for (m =0; m < cols; m++)
        cout<< image[k][m];
  for (k =0; k < rows; k++)
      for (m =0; m < cols; m++)
        cout<< image[k][m];

Last edited by twomers; Oct 15th, 2007 at 5:05 pm.

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Oct 15th, 2007

Re: Parallel Array/Reading In From A File

Hmm, the for loops to output the image to screen just throw it all out in a big mess, it loses its format of rows of 10 and columns of 22. I'll keep looking at it, here's my updated code:

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;
 
string filename;
int rows;
int cols;
int k = 0;
int m = 0;
string bum;
string row;
const int ROW_SIZE = 40;
const int COL_SIZE = 70;
char image [ROW_SIZE][COL_SIZE];
int main()
{
  ifstream inFile;
  cout << "Enter image file name:" << endl;
  getline(cin, filename);
  inFile.open(filename.c_str());
  inFile >> rows >> cols;
  inFile.ignore( 10, '\n');
  inFile >> image[k][m];
while (inFile){
  inFile >> image[k][m];
  for (k =0; k < rows; k++)
      for (m =0; m < cols; m++)
  inFile >> image[k][m];
  }
  for (k =0; k < rows; k++)
     for (m =0; m < cols; m++)
        cout<< image[k][m];
//  switch( image[k][m] )
//   {
//     case '0' : image[k][m] = ' ' ; break;
//     case '1' : image[k][m] = '-' ; break;
//     case '2' : image[k][m] = '=' ; break;
//     case '3' : image[k][m] = 'O' ; break;
//     case '4' : image[k][m] = 'Z' ; break;
//     case '5' : image[k][m] = 'X' ; break;
//     case '6' : image[k][m] = 'B' ; break;
//     case '7' : image[k][m] = '@' ; break;
//     case '8' : image[k][m] = 'W' ; break;
//     case '9' : image[k][m] = '#' ; break;
//   }
 
return 0;
}
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;

string filename;
int rows;
int cols;
int k = 0;
int m = 0;
string bum;
string row;
const int ROW_SIZE = 40;
const int COL_SIZE = 70;
char image [ROW_SIZE][COL_SIZE];
int main()
{
  ifstream inFile;
  cout << "Enter image file name:" << endl;
  getline(cin, filename);
  inFile.open(filename.c_str());
  inFile >> rows >> cols;
  inFile.ignore( 10, '\n');
  inFile >> image[k][m];
while (inFile){
  inFile >> image[k][m];
  for (k =0; k < rows; k++)
      for (m =0; m < cols; m++)
  inFile >> image[k][m];
  }
  for (k =0; k < rows; k++)
     for (m =0; m < cols; m++)
        cout<< image[k][m];
//  switch( image[k][m] )
//   {
//     case '0' : image[k][m] = ' ' ; break;
//     case '1' : image[k][m] = '-' ; break;
//     case '2' : image[k][m] = '=' ; break;
//     case '3' : image[k][m] = 'O' ; break;
//     case '4' : image[k][m] = 'Z' ; break;
//     case '5' : image[k][m] = 'X' ; break;
//     case '6' : image[k][m] = 'B' ; break;
//     case '7' : image[k][m] = '@' ; break;
//     case '8' : image[k][m] = 'W' ; break;
//     case '9' : image[k][m] = '#' ; break;
//   }

return 0;
}

I'm going to read up some more on switches, try and figure that out with what I have so far.

DemonSpeeding

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Oct 15th, 2007

Re: Parallel Array/Reading In From A File

Sorry! My bad:

C++ Syntax (Toggle Plain Text)
  for (k =0; k < rows; k++) {
      for (m =0; m < cols; m++)
        cout<< image[k][m];
  cout<< "\n";
}
  for (k =0; k < rows; k++) {
      for (m =0; m < cols; m++)
        cout<< image[k][m];
  cout<< "\n";
}

What I posted earlier just throws everything on one line but this should put a new like after every row. stupid mistake of mine. Sorry.

Last edited by twomers; Oct 15th, 2007 at 5:20 pm.

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Oct 15th, 2007

Re: Parallel Array/Reading In From A File

I read up on switches, and it says they're used for strings, not chars, so I'm going to have to do a bunch of if and else if statements then? Also this is what it's putting out for the image:

2288822288222222888222
2288822288222222888233
3333333333333333333311
1111111111111111111111
1114444411111111111111
1144444441155111111111
1464343434555111111111
1133333331155111111111
1113333311111111511411
11111111111111115543

It's almost right but there's something off about it. The first two digits are being cut off for some strange reason when it goes to output it.

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