Writing Struct to Binary File as a Save to Disk Operation

I've got a statistics management system that uses arrays of structures and I want to be able to close the program and reopen it without losing any data. My idea was to write all of the information to a binary file and then read it out of there each time the program is reopened.

Ive got an array of 5 structures with an array of structs within each of them. This may complicate things...... I can't figure out how to make it work. Any suggestions????????

Code:

---


#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>

#pragma warning (disable: 4995)
#pragma warning (disable: 4996)

FILE *out;
#define NUMUSERS 5

typedef struct rnd
{
        char  club[40];
        double slope;
        int    par;
        int    score;
        int    putts;
        int    fwyHit;
        int    grnHit;
        int    sandSave;
        int    numThrees;
        int    sandAttmpt;
        double rndHcp;
}  ROUND;

struct golfertype
{
        char  name[40];
        double handicap;
        int    totRounds;
        char  homeClub[40];
        double avgPutts;
        double avgFwys;
        double avgGreens;
        double sandSaves;
        int    sandRounds;
        ROUND  rnd[100];
};


void PrintVitals(struct golfertype *pt);
void EnterScore (struct golfertype *pt);
void ViewLast10(struct golfertype *pt);
void PrintLast10(struct golfertype *pt);


void main()
{
        int choice;
        char choice1;
        int choice2;
        char choice3;
        struct golfertype *golfer;// golfer1, golfer2, golfer3, golfer4, golfer5;
        ROUND rnd;
        int i;
        int a;
        int j;
        int numusers;
        size_t size;
        struct golfertype *pointer;
        FILE *save;

        save = fopen("save.dat","ab");
        fread(&golfer, sizeof(*golfer), 1, save);
        fclose(save);
       
        numusers = 5;
        golfer  = NULL;

    size    = numusers *  sizeof(golfertype);
        golfer = (golfertype *) realloc(golfer,size);

        strcpy( golfer[0].name, "Andrew Holtz" );
        golfer[0].avgFwys = 0;
        golfer[0].avgGreens = 0;
        golfer[0].avgPutts = 0;
        golfer[0].handicap = 0;
        strcpy( golfer[0].homeClub, "Pitt Meadows Golf Club" );
        golfer[0].sandRounds = 0;
        golfer[0].sandSaves = 0;
        golfer[0].totRounds = 0;

        strcpy( golfer[1].name, "Dan Thomson" );
        golfer[1].avgFwys = 0;
        golfer[1].avgGreens = 0;
        golfer[1].avgPutts = 0;
        golfer[1].handicap = 0;
        strcpy( golfer[1].homeClub, "Pitt Meadows Golf Club" );
        golfer[1].sandRounds = 0;
        golfer[1].sandSaves = 0;
        golfer[1].totRounds = 0;

        strcpy( golfer[2].name, "Terry Salchenberger" );
        golfer[2].avgFwys = 0;
        golfer[2].avgGreens = 0;
        golfer[2].avgPutts = 0;
        golfer[2].handicap = 0;
        strcpy( golfer[2].homeClub, "Pitt Meadows Golf Club" );
        golfer[2].sandRounds = 0;
        golfer[2].sandSaves = 0;
        golfer[2].totRounds = 0;

        strcpy( golfer[3].name, "Dustin Vernon" );
        golfer[3].avgFwys = 0;
        golfer[3].avgGreens = 0;
        golfer[3].avgPutts = 0;
        golfer[3].handicap = 0;
        strcpy( golfer[3].homeClub, "Pitt Meadows Golf Club" );
        golfer[3].sandRounds = 0;
        golfer[3].sandSaves = 0;
        golfer[3].totRounds = 0;

        strcpy( golfer[4].name, "Jesse Kurucz" );
        golfer[4].avgFwys = 0;
        golfer[4].avgGreens = 0;
        golfer[4].avgPutts = 0;
        golfer[4].handicap = 0;
        strcpy( golfer[4].homeClub, "Pitt Meadows Golf Club" );
        golfer[4].sandRounds = 0;
        golfer[4].sandSaves = 0;
        golfer[4].totRounds = 0;
       
       
        printf("\n[1] AndrewH");
        printf("\n[2] DanT");
        printf("\n[3] TerryS");
        printf("\n[4] DustinV");
        printf("\n[5] JesseK");

        printf("\nPlease choose you name/profile from the list: ");
        scanf("%d", &choice);

        switch(choice)
        {
                case 1:
                        i=0;
                        pointer = &golfer[i];
                        break;

                case 2:
                        i=1;
                        pointer = &golfer[i];
                        break;

                case 3:
                        i=2;
                        pointer = &golfer[i];
                        break;

                case 4:
                        i=3;
                        pointer = &golfer[i];
                        break;

                case 5:
                        i=4;
                        pointer = &golfer[i];
                        break;

        }

        fflush(stdin);

        PrintVitals( pointer );

        printf("\n\n\nTo view a menu press [M], to exit press [E]");
                scanf("%c", &choice1);
       
        if (choice1 == 'e' || choice1 == 'E')
        {
                save = fopen("save.dat", "ab");
                fwrite(&golfer, sizeof(*golfer), 1, save);
                fclose(save);
                exit(1);
        }
               
        else if (choice1 == 'm' || choice1 == 'M')
        {
        while (1)
                {
               
                printf("\n\n[1] Enter a score");
                printf("\n[2] View last 10 rnds");
                printf("\n[3] Print out the last 10 scores");
                printf("\n[4] View updated statistics");
                printf("\n[5] Exit the program");

                printf("\nPlease make a choice from the list: ");
                scanf("%d", &choice2);
               
                fflush(stdin);
               
        if (choice2 == 1)
        {
                EnterScore( pointer );
        }
       
        else if(choice2 == 2)
       
                ViewLast10(pointer);
               
        else if(choice2 == 3)
        {
                PrintLast10( pointer );
        }
        else if(choice2 == 4)
        {
                PrintVitals ( pointer );
        }

        else if (choice2 == 5)
        {
                save = fopen("save.dat", "ab");
                fwrite(&golfer, sizeof(*golfer), 1, save);
                fclose(save);
                exit(1);
        }
        }

        }
}




void EnterScore (struct golfertype *pt)
{
        int i;
        char choice3;
       
                if (pt->totRounds == 0)
                        i = (pt->totRounds);
                if (pt->totRounds > 0)
                        i = (pt->totRounds)-1;
       
                printf("Please enter the name of the golf club: ");
                gets( (pt->rnd[i]).club );

                fflush(stdin);
                printf("\nPlease enter the slope of the course: ");
                scanf("%lf", &(pt->rnd[i]).slope );

                fflush(stdin);
                printf("\nPlease enter the par of the course: ");
                scanf("%d", &(pt->rnd[i]).par);

                fflush(stdin);
                printf("\nPlease enter the number of par 3's the course has: ");
                scanf("%d", &(pt->rnd[i]).numThrees);

                fflush(stdin);
                printf("\nPlease enter your score: ");
                scanf("%d", &(pt->rnd[i]).score);
               
                fflush(stdin);
                printf("\nPlease enter the number of putts you had: ");
                scanf("%d", &(pt->rnd[i]).putts);

                fflush(stdin);
                printf("\nPlease enter the number of fairways that you hit: ");
                scanf("%d", &(pt->rnd[i]).fwyHit);

                fflush(stdin);
                printf("\nPlease enter the number of greens that you hit: ");
                scanf("%d", &(pt->rnd[i]).grnHit);

                fflush(stdin);
                printf("\nWere you in any green side traps today?(Y/N) ");
                        scanf("%c", &choice3);

                if (choice3 == 'y' || choice3 == 'Y')
                {
                        fflush(stdin);
                        printf("\nPlease enter the sand saves you had: ");
                        scanf("%d", &(pt->rnd[i]).sandSave);

                        fflush(stdin);
                        printf("\nPlease enter the number of sand traps you were in: ");
                        scanf("%d" , &(pt->rnd[i]).sandAttmpt);


                        pt->sandRounds++;
                        pt->sandSaves = ((double)(pt->sandSaves) + ((double)(pt->rnd[i]).sandSave / (double)(pt->rnd[i]).sandAttmpt)) / (double)(pt->sandRounds) * 100;

                }

                pt->totRounds++;
                pt->rnd[i].rndHcp = (pt->rnd[i]).score - (pt->rnd[i]).slope;
                pt->handicap += (pt->rnd[i]).rndHcp/((double)pt->totRounds);
                pt->avgPutts  = ((pt->avgPutts) + (double)(pt->rnd[i].putts))/((double)pt->totRounds);
                pt->avgFwys  = ((pt->avgFwys) + ((double)(pt->rnd[i]).fwyHit / (double)(18 - (pt->rnd[i]).numThrees))) / ((double)pt->totRounds) * 100;
                pt->avgGreens = (((pt->avgGreens) + ((double)(pt->rnd[i]).grnHit/18)) / ((double)pt->totRounds)) * 100;
}

void PrintVitals(struct golfertype *pt)
{
        printf("\n%s", pt->name);
        printf("\nHomeClub: %s", pt->homeClub);
        printf("\nHandicap: %.2lf", pt->handicap);
        printf("\nRounds Played: %d", pt->totRounds);
        printf("\nAverage Putts: %.2lf", pt->avgPutts);
        printf("\nPercent Average Fairways: %.2lf ", pt->avgFwys);
        printf("\nPercent Average Greens: %.2lf  ", pt->avgGreens);
        printf("\nPercentage Sand Saves: %.2lf  ", pt->sandSaves);
}

void ViewLast10 (struct golfertype *pt)
{
        int i,j;

        if (pt->totRounds > 10)
        {
                i = pt->totRounds - 1;

                for(j=0;j<10;j++)
                {
                        printf("\nClub: %s",(pt->rnd[i]).club);
                        printf("\nSlope: %.2lf",(pt->rnd[i]).slope);
                        printf("\nPar: %d",(pt->rnd[i]).par);
                        printf("\nScore: %d",(pt->rnd[i]).score);
                        printf("\nPutts: %d",(pt->rnd[i]).putts);
                        printf("\nFairways Hit: %d",(pt->rnd[i]).fwyHit);
                        printf("\nGreens Hit: %d",(pt->rnd[i]).grnHit);
                        printf("\nSand Saves: %d",(pt->rnd[i]).sandSave);
                        printf("\nSand Attempts: %d",(pt->rnd[i]).sandAttmpt);

                        i--;
                }
        }

                if (pt->totRounds < 10)
                {
                        i = pt->totRounds - 1;

                        while (i > -1)
                        {
                                printf("\nClub: %s",(pt->rnd[i]).club);
                                printf("\nSlope: %.2lf",(pt->rnd[i]).slope);
                                printf("\nPar: %d",(pt->rnd[i]).par);
                                printf("\nScore: %d",(pt->rnd[i]).score);
                                printf("\nPutts: %d",(pt->rnd[i]).putts);
                                printf("\nFairways Hit: %d",(pt->rnd[i]).fwyHit);
                                printf("\nGreens Hit: %d",(pt->rnd[i]).grnHit);
                                printf("\nSand Saves: %d",(pt->rnd[i]).sandSave);
                                printf("\nSand Attempts: %d",(pt->rnd[i]).sandAttmpt);

                        i--;
                        }
                }
        }
       
void PrintLast10(struct golfertype *pt)
{
        int i,j;
       
        i = pt->totRounds - 1;
               
        if (pt->totRounds > 10)
        {
                out = fopen("last10.txt", "w");

                for(j=0;j<10;j++)
                {
                        fprintf(out, "\n Club: %s",pt->rnd[i-9].club);
                        fprintf(out, "\n Slope: %.2lf",pt->rnd[i-9].slope);
                        fprintf(out, "\n Par: %d",pt->rnd[i-9].par);
                        fprintf(out, "\n Score: %d",pt->rnd[i-9].score);
                        fprintf(out, "\n Putts: %d",pt->rnd[i-9].putts);
                        fprintf(out, "\n Fairways Hit: %d",pt->rnd[i-9].fwyHit);
                        fprintf(out, "\n Greens Hit: %d",pt->rnd[i-9].grnHit);
                        fprintf(out, "\n Sand Saves: %d",pt->rnd[i-9].sandSave);
                        fprintf(out, "\n Sand Attempts: %d",pt->rnd[i-9].sandAttmpt);
                        i++;
                }
                fclose(out);
        }
       
        if (pt->totRounds < 10)
        {
                out = fopen("last10.txt", "w");
               
                while (i > -1)
                {
                                fprintf(out, "\nClub: %s",pt->rnd[i].club);
                                fprintf(out, "\nSlope: %.2lf",pt->rnd[i].slope);
                                fprintf(out, "\nPar: %d",pt->rnd[i].par);
                                fprintf(out, "\nScore: %d",pt->rnd[i].score);
                                fprintf(out, "\nPutts: %d",pt->rnd[i].putts);
                                fprintf(out, "\nFairways Hit: %d",pt->rnd[i].fwyHit);
                                fprintf(out, "\nGreens Hit: %d",pt->rnd[i].grnHit);
                                fprintf(out, "\nSand Saves: %d",pt->rnd[i].sandSave);
                                fprintf(out, "\nSand Attempts: %d",pt->rnd[i].sandAttmpt);
                                i--;
                        }
                        fclose(out);
                }
        }

---

Well I'm not much of a golfer, but as long as you're not doing anything complex like sharing the data between computers, the processing for binary files is usually a combination of fread and fwrite. You just have to dump the bytes in a temporary variable of the same type that was written prior. For example:

Code:

---

#include <stdio.h>
#include <stdlib.h>

struct record
{
    long int product_number;
    int in_stock;
    double product_price;
    char product_name[62];
};

int main (void)
{
    FILE * inf = NULL;
    struct record our_stock[] =
    {
        {
          0xBADF00D, 4, 1.99, "Bananas"
        },
        {
          0xDEADBEAF, 12, 15.00, "Steaks"
        },
        {
          0xDEAFD00D, 7, 2.50, "Leeks"
        },
    };

    /*** Open a file in binary mode (for reading or writing). ***/
    inf = fopen("foo.bin", "wb+");
    if (inf != NULL)
    {
        struct record aux;
        size_t idx;
        for (idx = 0; idx < sizeof our_stock / sizeof our_stock[0]; idx++)
        {
            /*** Use fwrite to dump our bogus data into a file.  Look it up! ***/
            fwrite(&our_stock[idx], sizeof(struct record), 1, inf);
        }

        /*** Start reading from the beginning of the file: ***/
        rewind(inf);
        while (fread(&aux, sizeof(struct record), 1, inf) > 0)
        {
            printf("ITEM: %-10.62s QTY: %03ld PRICE: $%6.4g ID: %-12X\n",
                aux.product_name, aux.in_stock, aux.product_price, aux.product_number);
        }
        fclose(inf);
        remove("foo.bin");
    }
    return 0;
}

---

As expected, I've successfully written and read a binary file. The output is of little interest, but that's just to show you it's possible.

Don't use fflush(stdin). Undefined behavior.