Deleting a line from a file

I have a program that is supposed to delete records from a file, I tried opening the file to read and write and using fgets to input each line. I'd then sscanf the input to a string and test to see if one of the items in the line is the record. If it is then I use continue to skip it and if it isn't then I fputs the line back into the file.

Supposedly this should leave the file as it was except without the one line I wanted to delete, but it's not working at all. Here's the code

Code:

---

int delete_rec()
{
        FILE*fpt;
        unsigned long number;
        char buffer[500],
                pInput[500];
        struct cust TEMP;

        printf("\nDELETE RECORD");

        if(!(fpt=fopen("cust.dat","rw"))){
                printf("Error opening cust.dat for delete");
                return (1);
        }

        printf("\nCustomer Number:");
        scanf("%d", &number);
        fflush(stdin);
       
        while(fgets(buffer, sizeof(buffer), fpt) != NULL){
                sscanf(pInput, "%d%*c%49[^;]%*c%49[^;]%*[^OoSs]%c", &TEMP.no, TEMP.name,
                        TEMP.add, &TEMP.status);
                if(TEMP.no == number)
                        continue;
                fputs(buffer, fpt);
        }

        if(fclose(fpt) == EOF){
                printf("Error closing file\a\n");
                return 1;
        }
        printf("\n\nDeleted. Press ENTER to continue.\n");
        getchar();

        return 0;
}

---

Update:
I found a problem with the loop, but it still doesn't work, here's the change.

Code:

---

        while(fgets(buffer, sizeof(buffer), fpt) != NULL){
                strncpy(pInput, buffer, 500);
                sscanf(pInput, "%d%*c%49[^;]%*c%49[^;]%*[^OoSs]%c", &TEMP.no, TEMP.name,
                        TEMP.add, &TEMP.status);
                if(TEMP.no == number){
                        ;
                }else{
                        fputs(buffer, fpt);
                }
        }

---

It's very hard to modify a text file like this, because line lengths can change.

It's much simpler to simply create another file with all the changes, then do a delete/rename when you're done.