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Message Board > C/C++ > help reading .txt files

July 2, 2013, 04:22
DoctorN
Whiskered
91 posts
Code:
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
1,0,0,1,1,1,1,0,0,0,0,0,1,1,1,1,1,0,0,1
1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1
1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1
1,0,0,1,0,0,0,1,1,1,0,0,0,0,0,0,1,0,0,1
1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1
1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1
1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1
1,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,1
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 


Here is my .txt file

Code:
int lvlWidth;
int lvlHeight;

void create::render_level( string levelFile )
{
    //The width and height of the level
    lvlWidth = 20;
    lvlHeight = 15;

    //Create a 2D array based on the size of the level
    int** level;
    level = new int*[lvlWidth];
    for (int i = 0;i<lvlWidth;i++)
    level[i] = new int[lvlHeight];

    //Open the level
    ifstream lvlFile;
    lvlFile.open( levelFile.c_str() );

    //If the level fails to open
    if( !lvlFile )
    {
        cout << "File open failed!\n";
    }

    int i = 0; int j = 0; char line[300];

    //Read the file
    while( lvlFile.getline(line, sizeof line) )
    {
        //cout << line << endl;
        for( j = 0; j < lvlWidth; ++j )
        {
            sscanf( line+(j*2), "%d%*c", &level[i][j] );
        }
        ++i;
    }

    //Place things on the level
    for( i = 0; i < lvlWidth; i++ )
    {
        for( j = 0; j < lvlHeight; j++ )
        {
            if( level[j][i] == 1 ) //Place a block when level[i][j] is not 0
            {
                lvlbox[j*20+i].x = (i*16);
                lvlbox[j*20+i].y = (j*16);
                lvlbox[j*20+i].w = 16;
                lvlbox[j*20+i].h = 16;
                //If there is a place for a block, say where it is
                //cout << "lvlbox[" << ((j*20+i+1)) << "] is at coordinates: " << lvlbox[j*20+i].x << "," << lvlbox[j*20+i].y << endl;
            }
        }
    }

    //Close the file
    lvlFile.close();

    //Set the way for objects to be placed
    initialized = false;


Here is the code that reads the level

Code:
for( int i = 0; i < lvlWidth; i++ )
{
    for( int j = 0; j < lvlHeight; j++ )
    {
        SDL_FillRect( screen, &lvlbox[j*20+i], SDL_MapRGB( screen->format, 0x00, 0x00, 0x00 ) );
    }


Here is the code that renders it to screen. Now you may see lvlbox[j*20+i], just change it to lvlbox[j*lvlWidth+i]. I need help with the following:

1. counting the number of characters per line while excluding the comma (or counting the commas seperately and then subtracting the total by the number of commas, whatever is easier). I also need something to count the number of lines. The reason being is I want to be able to put the number of characters in lvlWidth and the number of lines in lvlHeight.

2. what if I decide to have double digits between the commas? like 01 instead of 1. how would I be able to do that? (going back to no. 1, how could i still put it into lvlWidth, just divide the total by 2 or something?)

3. I may be getting ahead of myself, but if I were to make "-end-" the last line of the .txt file, how could I make the code understand that (while not counting -end- as another line, because I would like to put variables after -end-)?

Thanks
____________
#
July 3, 2013, 06:21
DoctorN
Whiskered
91 posts
could you also show me how to count this?
Quote:

01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01
01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01


thanks
____________
#
July 10, 2013, 17:27
DTM
Earthling!
823 posts

I can't answer anything precisely because I'm too lazy. However here are some pointers.

1.) um, just count the commas?

int commaCount = 0;
for (int i = 0; line[i] != 0; i++)
{
if (line[i] == ',')
commaCount ++;
}

The total number of numbers on a line is obviously commaCount plus one.

2) personally I would be using strtok or something
http://www.cplusplus.com/reference/cstring/strtok/

split each line by commas, and then pass each sub string to some function to convert strings to numbers:
http://www.cplusplus.com/reference/cstdlib/atoi/

3) http://www.cplusplus.com/reference/cstring/strstr/

while iterating through the lines:

if (strstr(line, "-end-") != 0) // "-end-" was found in the line string
{
...do something different
}


There are a lot of other string functions too. Study them all.
http://www.cplusplus.com/reference/cstring/


Or if you want to operate on proper C++ style string objects (rather than old school C arrays), you can use the methods of the String class:
http://www.cplusplus.com/reference/string/string/

e.g. you might use String.find rather than strstr()
http://www.cplusplus.com/refer … ng/string/find/

if (std::string(line).find("-end-") != std::string::npos)
{
// "-end-" was found
}


standard disclaimer applies that I don't really have a clue what you are doing since i didn't study it closely.
____________
:o
#
July 10, 2013, 17:36
DTM
Earthling!
823 posts

You also might look for a nice C++ library that has lots more utility functions. E.g. Boost.

Boost has a "split" function which could be used for splitting by commas or whatever:
http://www.boost.org/doc/libs/ … tring_algo.html
http://www.boost.org/doc/libs/ … algo/usage.html

also several different answers for splitting a line here:
http://stackoverflow.com/quest … e-a-string-in-c

[Edited on July 10, 2013 by DTM]
____________
:o
#
July 12, 2013, 19:23
DoctorN
Whiskered
91 posts
Thanks
____________
#

Message Board > C/C++ > help reading .txt files

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