1. We have moved from vBulletin to XenForo and you are viewing the site in the middle of the move. Though the functional aspect of everything is working fine, we are still working on other changes including the new design on Xenforo.
    Dismiss Notice

How do you point to a const char array with the name in an array?

Discussion in 'C' started by dfansler, Aug 17, 2012.

  1. dfansler

    dfansler New Member

    Joined:
    Aug 17, 2012
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    0
    Home Page:
    I am doing some work with a LCD graphic display and a microcontroller. I have defined the alphabet in a series of constant char arrays that tell me what bits to turn on or off to display that character - ie. for '0' (0x30)

    const char CS22PT_0x30[122] ={18,40,
    0x00,0x00,0x00,0x00,x00,0x10, etc.........
    }
    The first two numbers are the x and y size of the character. I call this array by
    char far *name
    name = &CS22PT_0x30;
    Display_Graphic(name);

    And this works. As long as I know ahead of time what the name of the const char array I am calling is.

    So the next step was to take a char array containing the string I want to display and determine which const char array to call on the fly rather than hard coding it in.

    What I have so far is an array predfined as
    char text_1[] = {"Night's Beautiful Daughter"};

    I set a pointer to the array
    char *t_to_d;
    t_to_d = &text_1[0];

    call a function that uses that pointer and the name of the font to use
    write_text(t_to_d,font_22)

    font_22 was previously defined as
    char font_22[]={"CS22PT"};

    the write_text fucntion then converts (starting with the first character of text_1[0]) into a hex value that is cat onto the font name. ie Since the first character in text_1 is 'N' which is 0x4e in hex, I get an array that contains CS22PT_0x4e

    FINALLY I can ask the question!!
    How do I use the string "CS22PT_0x4e" in the array to point to the const char CS22PT_0x4e so I can get the data out of const char CS22PT_0x4e?

    Thanks,
    David
     
  2. debugEnthu

    debugEnthu New Member

    Joined:
    Jul 5, 2012
    Messages:
    11
    Likes Received:
    3
    Trophy Points:
    0
    Hi,

    Which language are u using??/

    In case you are using C++ you canuse STL map containers

    map<unsigned int, char *> mymap.

    Here key (unsigned int) would be hex representation of character...n your example - 0x4e
     
  3. dfansler

    dfansler New Member

    Joined:
    Aug 17, 2012
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    0
    Home Page:
    opps - I am writing in C.
    Thanks,
    David
     

Share This Page