can I do this?

This is a discussion on can I do this? within the C++ Programming forums, part of the General Programming Boards category; I'm working on a program that modifies images. It's a very simple program that uses 2d arrays and all that ...

  1. #1
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    can I do this?

    I'm working on a program that modifies images. It's a very simple program that uses 2d arrays and all that fun stuff. I'm trying to transpose (rotate it 90 degrees one way), however, when I make that selection (in .exe) the program just hangs... here is my transpose function:

    void transpse(Pixel image_mod[][800], int w, int h)
    {
    Pixel transposed[MAXW][MAXH];

    for(int i = 1; i < w; i++)
    {
    for(int j = 1; j < h; j++)
    {
    transposed[j][i] = image_mod[i][j];
    }
    }

    for(int i = 1; i < w; i++)
    {
    for(int j = 1; j < h; j++)
    {
    image_mod[i][j] = transposed[i][j];
    }
    }
    }
    -----------------------------------------------------------------------------
    it all seems correct...but it doesn't do anything... Do you guys see anything?? Let me know if you want to see anything else.

    SAW

  2. #2
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    hehehe...silly me... Okay, my problem wasn't with my void function it was with my while loop in my selection menu... let me show you:
    -----------------------------------------------------------------------------
    cout << "You can now modify the image you chose with the following choices: " << endl;
    cout << "You can keep making changes to the picture until you get tired." << endl;
    cout << "\t S - Smooth" << endl;
    cout << "\t T - Transpose (Turn the image to the side)" << endl;
    cout << "\t D - Dither (create a checkerboard effect)" << endl;;
    cout << "\n brightest to darkest. The image will be no more.)" << endl;
    cout << "\t G - Gray Scale (makes the image gray)" << endl;
    cout << "\t E - Exit modifications." << endl;
    cin >> menu;
    while(menu != 'E')
    {
    switch(menu)
    {
    case 'D':
    {
    dither(image, W, H);
    break;
    }
    case 'G':
    {
    make_grey(image, W, H);
    break;
    }
    case 'S':
    {
    smooth(image, W, H);
    break;
    }

    case 'T':
    {
    transpose(image, W, H);
    break;
    }
    }
    }

    -----------------------------------------------------------------------------
    )okay...so now...my question is. How do I make it to where I can keep chosing and it keeps going through until some one makes a choice to exit??

    SAW

  3. #3
    Linguistic Engineer... doubleanti's Avatar
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    put the input statement in the while, before the switch... if you choose to put it at the end of the while, preset the input variable as a precaution since an uninitialized variable could very well have the exit command as a value...
    hasafraggin shizigishin oppashigger...

  4. #4
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    there's an input statement before the while...

    SAW

  5. #5
    Skunkmeister Stoned_Coder's Avatar
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    You could add another case to your menu.....

    case q: exit(0);

    this will cause your program to exit. you need stdlib.h or cstdlib included.
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  6. #6
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    well..my problem now is that I can make numerous choices...but it'll only do the first choice. It won't do any other ones after making the first choice...

    SAW

  7. #7
    Linguistic Engineer... doubleanti's Avatar
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    there's a check of the input, but no refresh of the input... post your latest source so we get a better idea of how to mold your code correctly...
    hasafraggin shizigishin oppashigger...

  8. #8
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    Okie...this is my entire code... except for the .h files. sorry if it's very long.

    ---------------------------------------------------------------------------------

    #include <iostream>
    #include <string>
    #include "Pixel.h"

    using namespace std;

    const int MAXH = 800;
    const int MAXW = 800;

    void read_header(ifstream& fin, ofstream& fout, int& width, int& height, int& max);
    void make_grey(Pixel image_mod[][800], int w, int h);
    void dither(Pixel image_mod[][800], int w, int h);
    void smooth(Pixel image_mod[][800], int w, int h);
    void transpose(Pixel image_mod[][800], int w, int h);
    void make_purple(Pixel image_mod[][800], int w, int h);
    void make_blue(Pixel image_mod[][800], int w, int h);
    void make_green(Pixel image_mod[][800], int w, int h);
    void make_bright(Pixel image[][800], int w, int h, int color);

    int main()
    {
    Pixel image[MAXW][MAXH];
    ifstream fin;
    ofstream fout;
    int W, H, colormax;
    string image_file;
    char menu, anykey;

    cout << "Please enter the name of the image you'd like to use: " << endl;
    cin >> image_file;

    if(fin.fail())
    {
    cout << "File was unable to open. Check syntax and try again." << endl;
    return 0;
    }

    cout << "Gathering Data from the image, please wait." << endl << endl;

    fin.open(image_file.c_str());
    image_file= "mod_" + image_file;
    fout.open(image_file.c_str());

    read_header(fin, fout, W, H, colormax);

    for(int column = 0; column < W; column++)
    {
    for(int row = 0; row < H; row++)
    {
    fin >> image[column][row];
    }
    }

    cout << "You can now modify the image you chose with the following choices: " << endl;
    cout << "You can keep making changes to the picture until you get tired." << endl;
    cout << "\t S - Smooth" << endl;
    cout << "\t T - Transpose. Will turn the image to the side)" << endl;
    cout << "\t D - Dither, creates a checkerboard effect." << endl;
    cout << "\t b- Brighten, will brighten or darken the image." << endl;
    cout << "\t g - Make the image gray." << endl;
    cout << "\t P - Make the image purple." << endl;
    cout << "\t B - Make the image blue." << endl;
    cout << "\t G - Make the image green." << endl;
    cout << "\t O - Make other." << endl;
    cout << "\t E - Exit modifications." << endl;
    cout << "\nYour Selection: " << endl;

    cin >> menu;

    while(menu != 'E')
    {
    switch(menu)
    {
    case 'D':
    {
    dither(image, W, H);
    break;
    }
    case 'g':
    {
    make_grey(image, W, H);
    break;
    }
    case 'S':
    {
    smooth(image, W, H);
    break;
    }
    case 'T':
    {
    transpose(image, W, H);
    break;
    }
    case 'P':
    {
    make_purple(image, W, H);
    break;
    }
    case 'B':
    {
    make_blue(image, W, H);
    break;
    }
    case 'G':
    {
    make_green(image, W, H);
    break;
    }
    case 'b':
    {
    make_bright(image, W, H, colormax);
    break;
    }
    }

    for (int columnout = 0; columnout < W; columnout++)
    {
    for(int rowout = 0; rowout < H; rowout++)
    {
    fout << image[columnout][rowout];
    }
    }
    cout << "Make another selection or E to exit." << endl;
    cin >> menu;
    }
    cout << "Hit any key to exit." << endl;
    cin >> anykey;
    fin.close();
    fout.close();
    return 0;
    }
    //************************************************** ***********************
    void read_header(ifstream& fin, ofstream& fout, int& width, int& height, int& max)
    {
    char header[100];
    char ch;
    /* get magic number */
    fin.getline(header, 100);
    /* write magic number */
    fout << header << endl;
    cout << header << endl;

    /* get all comment lines and write to new file */
    fin >> ch;
    while(ch == '#')
    {
    fin.getline(header, 100);
    fout <<ch << header << endl;
    cout << ch <<header << endl;
    fin >> ch;
    }
    fin.putback(ch);
    /* input width and height of image */
    fin >> width >> height;
    cout << width <<" " << height << endl;
    fout << width << " " << height << endl;
    /* input maximum color value */
    fin >> max;
    cout << max << endl;
    fout << max << endl;
    return;
    }

    void make_grey(Pixel image_mod[][800], int w, int h)
    {
    int grey;
    for(int i = 0; i < h; i++)
    {
    for(int j = 0; j < w; j++)
    {
    grey = (image_mod[i][j].get_red()+image_mod[i][j].get_blue()+
    image_mod[i][j].get_green())/3;
    image_mod[i][j].set_pixel_value(grey, grey, grey);
    }
    }
    }
    void dither(Pixel image_mod[][800], int w, int h)
    {
    bool z;
    int x, y;
    for (x=0; x < w; x++)
    {
    z=x%2;
    for(y=0; y < h; y++)
    {
    if(z!=0)
    {
    image_mod[x][y].set_pixel_value(0,0,0);
    z =0;
    }
    else
    z=1;
    }
    }
    }

    void smooth(Pixel image_mod[][800], int w, int h)
    {
    for(int i = 1; i < h-1; i++)
    {
    for(int j = 1; j < w-1; j++)
    {
    image_mod[i][j] = (image_mod[i][j]+image_mod[i-1][j]+image_mod[i+1][j]+
    image_mod[i][j-1]+image_mod[i][j+1]+image_mod[i][j]+
    image_mod[i+1][j+1]+image_mod[i-1][j-1]+image_mod[i+1][j-1])
    /9;
    }
    }
    }

    void transpose(Pixel image_mod[][800], int w, int h)
    {
    //int maxfill = 800;
    Pixel transposed[MAXW][MAXH];

    for(int i = 1; i < w; i++)
    {
    for(int j = 1; j < h; j++)
    {
    transposed[j][i] = image_mod[i][j];
    }
    }

    for(int i = 1; i < w; i++)
    {
    for(int j = 1; j < h; j++)
    {
    image_mod[i][j] = transposed[i][j];
    }
    }
    }

    void make_purple(Pixel image_mod[][800], int w, int h)
    {
    int purple;
    for(int i = 0; i < h; i++)
    {
    for(int j = 0; j < w; j++)
    {
    purple = (image_mod[i][j].get_red()+image_mod[i][j].get_blue()+ image_mod[i][j].get_green())/3;
    image_mod[i][j].set_pixel_value(purple, 0, purple);
    }
    }
    }

    void make_blue(Pixel image_mod[][800], int w, int h)
    {
    int blue;
    for(int i = 0; i < h; i++)
    {
    for(int j = 0; j < w; j++)
    {
    blue = (image_mod[i][j].get_red()+image_mod[i][j].get_blue()+ image_mod[i][j].get_green())/3;
    image_mod[i][j].set_pixel_value(0, 0, blue);
    }
    }
    }

    void make_green(Pixel image_mod[][800], int w, int h)
    {
    int green;
    for(int i = 0; i < h; i++)
    {
    for(int j = 0; j < w; j++)
    {
    green = (image_mod[i][j].get_red()+image_mod[i][j].get_blue()+ image_mod[i][j].get_green())/3;
    image_mod[i][j].set_pixel_value(0, green, 0);
    }
    }
    }

    void make_bright(Pixel image[][800], int w, int h, int color)
    {
    double bright;
    char anykey;

    cout << "In order to make this function work properly, please enter "
    << "\na brightness multiplier. The mulitplier has to be between 0 and 2."
    << "\nAnything less than one will darken the image. Anything higher than "
    << "\n1 will brighten it. The numbers can be in decimal form as well." << endl;
    cin >> bright;

    if (bright< 0 || bright >2)
    {
    cout << "Modifier out of range. Quitting Function." << endl;
    return;
    }

    for (int i = 0; i < h; i++)
    {
    for (int j = 0; j < w; j++)
    {
    image[i][j] = image[i][j]*bright;
    if(image[i][j].get_red() > color)
    image[i][j].set_red(color);
    if(image[i][j].get_green() > color)
    image[i][j].set_green(color);
    if(image[i][j].get_blue() > color)
    image[i][j].set_blue(color);
    }
    }
    cout << "Hit any key to exit." << endl;
    cin >> anykey;
    }
    -----------------------------------------------------------------------------------

    There it is...

    SAW

  9. #9
    Unregistered
    Guest
    You should put "cin >> menu;" inside the 'while' loop, otherwise it'll only get executed once!

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