Thread: Help please!

Well for starters you're still doing this wrong:

Code:

fwrite(mainm, 1, sizeof(struct database) * 10, fp);

I've already told you this once. Now let's pay attention this time:

Code:

fwrite( fromhere, sizeofoneobject, howmanyobjects, file );

Furthermore, at a glance, you don't even have a function called:

Code:

void fflushstdin( void );//clears scanf when called

defined any place in your code. You prototype it, but it's not actually in any of the code you have posted.

And finally, just saying "doesn't seem to be working properly" doesn't really help us pinpoint the problem. It also doesn't really inspire me to find an old DOS compiler around just so I can compile your code. It doesn't really want to even make me comment out all of the non-standard stuff just to compile it either.


Quzah.

I guess I was a little more inspired than quzah to fix up your code so it would compile on my machine. Maybe I had a little too much time on my hands. When you have problems - the kind which we can only assume what they are - do as was implied, and post warning messages and so on to help us. The other suggestion would be to pare down your code, to get a small working example - then add your features such as text colour and screen effects and so on. Here is some revised code, with comments:

Code:

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

struct database {
        char prod[60];
        float cal;
        float carb;
        float prot;
        float fat;
};

static float getnum(void);

int main(void)
{

        enum {
                MAX = 10
        };

        struct database mainm[MAX];

        char *p;
        int ;
        FILE *fp;

        for (j = 0; j < MAX; j++) {

                (void) system("cls");
                printf("\nEnter the product: ");
                (void) fflush(stdout);
                (void) fgets(mainm[j].prod, 60, stdin);
                if ((p = strchr(mainm[j].prod, '\n')) != NULL) {
                        *p = '\0';
                }
                (void) system("cls");

                printf("\nNow Please Enter The Nutritional Information: ");
                (void) fflush(stdout);

                printf("\nEnter cal: ");
                (void) fflush(stdout);
                mainm[j].cal = getnum();

                printf("\nEnter carb: ");
                (void) fflush(stdout);
                mainm[j].carb = getnum();

                printf("\nEnter protein: ");
                (void) fflush(stdout);
                mainm[j].prot = getnum();

                printf("\nEnter fat: ");
                (void) fflush(stdout);
                mainm[j].fat = getnum();
        }

        (void) system("cls");

        fp = fopen("output.dat", "ab");
        if (fp == NULL) {
                perror("Unable to open file");
                exit(EXIT_FAILURE);
        }
        fwrite(mainm, sizeof(struct database), MAX, fp);
        if (fclose(fp) != 0) {
                perror("fclose");
                exit(EXIT_FAILURE);
        }

        fp = fopen("output.dat", "rb");
        if (fp == NULL) {
                perror("Unable to open file");
                exit(EXIT_FAILURE);
        }
        fread(mainm, sizeof(struct database), MAX, fp);
        if (fclose(fp) != 0) {
                perror("fclose");
                exit(EXIT_FAILURE);
        }

        for (j = 0; j < MAX; j++) {
                (void) system("cls");
                printf
                    ("\n * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *");
                printf
                    ("\n\nThe nutritional values for item #%d (%s) are: \n\n",
                     i + 1, mainm[j].prod);
                printf("CALORIES - %.2f\n", mainm[j].cal);
                printf("CARBOHYDRATES - %.2f\n", mainm[j].carb);
                printf("PROTEIN - %.2f\n", mainm[j].prot);
                printf("FAT - %.2f\n\n", mainm[j].prot);
                printf
                    ("\n* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *");
                printf("\n\nPress return for next product...\n");

                (void) getchar();

        }

        return 0;
}


static float getnum(void)
{

        enum {
                BUFMAX = 12
        };
        char *p;
        char buf[BUFMAX] = { (char) 0 };
        float num;

        (void) fgets(buf, BUFMAX, stdin);
        if ((p = strchr(buf, '\n')) != NULL) {
                *p = '\0';
        }

        if ((sscanf(buf, "%f", &num)) != 1) {
                (void) puts("Error: call to sscanf() failed.");
                exit(EXIT_FAILURE);
        } else {
                return num;
        }
}

A lot of the changes were stylistic I suppose, but it helps make things more clear.

1 - Try to use named constants instead of 'magic numbers' in your code. You had things like

Code:

for ( i = 0; i < 10; i++)

While this is not evil or anything, if 10 is a meaningful number (and in this case it is) try making it into a #define or an enum such as I did:

Code:

 enum {
                MAX = 10
        };

....

for ( i = 0; i < MAX; i++)

That way, if you need to change the 'max' value, you need only change it in one spot, rather than several. By doing this, you don't have to search through your code looking for the relevant bits to change.

If you have an operation that you need to do several times, consider turning it into a separate function, such as the one I wrote, getnum(). If you look at the getnum() function, you will notice that I checked the return value of sscanf() - scanf() also returns the number of successful data conversions, and if you must use scanf(), always check that return value!

Speaking of return values, you did not check the returns from fopen() and fclose() - that is bad.

There are other changes I made, but there were enough that I cannot remember them all. Have a look over the code, and if there is anything you don't understand, just ask.

edit::

Here is something kind of glitchy - I was using i for the one variable, but when I would do this:

Code:

(void) fgets(mainm[i].prod, 60, stdin);

it was being interpreted as an opening italics tag - then the rest of the message was italicized. I assume this has been noticed before, or should I add it to the bugs page?
~/