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From: KTrumpetsRule AT cs DOT com
Message-ID: <1f2.777c338.2f8c63a9@cs.com>
Date: Mon, 11 Apr 2005 19:35:05 EDT
Subject: Re: problem with saving struct to disk
To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

>I'm having a problem saving a struct to disk using DJGPP.  Normally I'd 
think 
>the problem was me but in view of the fact that it works under SOME 
>circumstances, I'm not sure.  Here's the details.
>
>  
>
looks like someones homework :-)

As a matter of fact, ....  No, actually I'm attempting to write an engine 
simulation program and a drag race simulation program.  I had already done most 
of the work in QuickBASIC 4.5 when I opted to try to learn C so that I could 
compile it on other platforms (Linux, mostly for the clustering ability).  

Soooo, here's the kicker.  I'm also using 2 other struct's.  Here's one of 
them:

/* -----------------12/24/04 1:46PM------------------
    this is permanent structure and saved to disk with
        file extension .KRM
 --------------------------------------------------*/
#ifndef BIKE_MAIN_H         /* these factors normally aren't changeable */
#define BIKE_MAIN_H

    #ifndef GLOBAL_BIKE_MAIN
        extern
    #endif

    struct bike_main {

        char filename[12];      /* 8 + . + 3    */

        float wgt;          /* weight of bike and rider */
        float wb;           /* wheelbase */
        float cgx;          /* horizontal center of gravity */
        float cgy;          /* vertical center of gravity */

        float p;            /* primary gear ratio */
        unsigned short y;   /* number of gears */
        float g[15];        /* gear ratios */

        float a;            /* aerodynamic drag factor */
        float b;            /* aerodynamic drag factor */
        float c;            /* aerodynamic drag factor */

        char bike_main_note_1[70];
        char bike_main_note_2[70];
        char bike_main_note_3[70];
        char bike_main_note_4[70];
        char bike_main_note_5[70];
        char bike_main_note_6[70];
    } bike_main_0 ;

    typedef struct bike_main BIKE_MAIN;
    BIKE_MAIN bike_main_0;

#endif

The get, save, read, and display functions are all exactly the same as per my 
previous post except the filename and extension gets changed (all I did was 
cut and paste).   Those exact same routines work exactly as expected with the 
other 2 struct.

Here's an  example of how I'm calling those functions:

/* -----------------3/4/05 8:51AM--------------------
    this menu allows user to read data from file
 --------------------------------------------------*/
void file_read_menu(void)
{
    int ans = 0;
    int max_len = 0;
    char string[max_len];

    while (1)
    {
        char sec_name[]="Read Data from FILE";
        heading(sec_name);

        clr_area(4,22,1,78);

        locate(5,5);
        printf("Read Basic Bike Data From File ......................... 1");
        locate(6,5);
        printf("Read Variable Bike/Launch Data From File ............... 2");
        locate(7,5);
        printf("Read RPM/Torque/Horsepower Data From File .............. 3");

        locate(17,5);
        printf("RETURN TO PRIOR MENU ................................... R");

        locate(20,5);
        printf("Enter your choice - ");

        get_input(20, 26, string, 2);

        if ((*string == 'r') || (*string == 'R'))
        {
            return ;
        }
        ans = atoi(string);

        switch (ans)
        {
            case 1:                     /* read basic bike data */
                file_read_basic(&bike_main_0);
                break;
            case 2 :                    /* read variable data */
                file_read_opt(&bike_opt_0);
                break;
            case 3 :                    /* read torque/hp data */
                file_read_power(&power_0);
                break;
            default:
                wrong();
                break;
        }
    }
    return ;
}


Does this additional info help?

Willy

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