c - Record add/show/delete for file functions not working -

-

the question's title pretty explains situation. not used using files , associated commands (such fseek, fwrite, etc).

anyhow, following program must simulate menu, , present user choice of either adding, editing, deleting or showing records file. rather simplistic task, can't figure out i'm doing wrong. 

 #include <stdio.h>   typedef struct{  int code;  char description[100];  int volume; }product;    int main() {    int pick =0, i; product *p; file *fileptr;  void add(file *fileptr, product* p); void removal(file *fileptr, product* p); void show(file *fileptr, product* p); void edit(file *fileptr, product* p); void description(file *fileptr, product* p);   if ( ( fileptr = fopen( "stock.dat", "rb+")) == null ) {     printf("the file not read"); } else {   do{    printf("    ************ main menu ************\n");    printf("  ** -------------welcome------------- **\n");    printf(" **                                      ** \n");    printf("*  please select 1 of commands below *\n");    printf("********************************************\n");    printf("* press 1 remove products list *\n");    printf("* press 2 change product's quantity   *\n");    printf("* press 3 add new product list *\n");    printf("* press 4 view product list             *\n");    printf("* press 5 exit programm             *\n");    printf("********************************************\n");    scanf("%d", &pick);     switch ( pick ) {     case 1:       removal(fileptr, p);     break;     case 2:       edit(fileptr, p);     break;     case 3:      add(fileptr, p);    break;     case 4:      show(fileptr, p);    break;         default:       printf("error! please enter correct number");    break;  }  }while (pick != 5);    }     fclose(fileptr);   return 0; }   void removal(file *fileptr, product * p) {     int code;       product empty = { 0, " ", 0 };      printf("\n\nyou delete record, please enter product's code");     scanf("%d", &code);      fseek( fileptr, (code - 1) * sizeof(p), seek_set);     fread( &p->code, sizeof(p), 1, fileptr);      if (p->code == 0){         printf("product code not found, please retry");     } else {         fseek( fileptr, (code -1) * sizeof(p), seek_set);          fwrite( &empty, sizeof(p), 1, fileptr);          printf("code found, product removed successfully\n\n");     } }   void add(file *fileptr, product * p){    int code, quantity;    printf("you add new product in list\n please input product's code\n");    scanf("%d", &code);     fseek( fileptr, (code-1) * sizeof(p), seek_set);   fread(&code, sizeof(p), 1, fileptr);       fseek(fileptr, (code-1) * sizeof(p), seek_set);     fwrite( &code, sizeof(p), 1, fileptr);      printf("now enter product's remaining quantity");     scanf("%d", &quantity);      fseek(fileptr, (quantity-1) * sizeof(p), seek_set);     fwrite( &quantity, sizeof(p), 1, fileptr);       }    void edit(file *fileptr, product * p){    int code, volume;    printf("\nyou edit existing product's quantity\n please enter product's code\n");   scanf("%d", &code);    fseek(fileptr, (code -1) * sizeof(p), seek_set);   fread(&code, sizeof(p), 1, fileptr);    if (p->code == 0){     printf("\nthe code entered not in list, please retry\n");   }else{     printf("\ncode found!\n product's  current quantity %d", &p->volume);     printf("\n please enter new quantity");     scanf("%d", &volume);      p->volume = volume;       fseek(fileptr, (volume -1) * sizeof(p), seek_set);     fwrite(&volume, sizeof(p), 1, fileptr);      }    }   void show(file *fileptr, product * p){   int i=1;    printf("\n\n\n               ****showing products****\n\n\n");  printf("product code      quantity in stock\n");     while (i<100 && !feof(fileptr)){     fscanf( fileptr, "%d%d", &p->code, &p->volume);     printf("%d            %d\n", &p->code, &p->volume);     fseek(fileptr, (p->code + 1) * sizeof(p), seek_set);     fscanf( fileptr, "%d%d", &p->code, &p->volume);     i++;    }  printf("you may scroll view list\n\n");   }

to give idea of happening: if user enters option 4, program, instead of showing no records, shows random values, if user chooses add product (by picking choice 3, add function), won't shown later , result, can't deleted if user chooses so. again, i'm rather new @ programming (i sure hear lot :p). had posted similar question before, did not solution.

edit edited big portion of code, file opens in binary , now, struct product p, passes each function. problem supposedly fixed, program run once showing correct values , records, crashes uknown reason. additional great

there's problem show function...

for starters, make following changes (marked using comment):

void show(file *fileptr){      typedef struct{         int code;         char description[100];         int volume;     } product;      product p;      int i=1;      // removed re-opening of file       printf("\n\n\n               ****showing products****\n\n\n");     printf("product code      quantity in stock\n");      // moved first fscanf() while loop     while (i<100 && !feof(fileptr)){         fscanf( fileptr, "%d%d", &p.code, &p.volume);         printf("%d            %d\n", &p.code, &p.volume);         fseek(fileptr, (p.code + 1) * sizeof(p), seek_set);         i++;     }     printf("you may scroll view list\n\n");  }

Comments

Post a Comment

Popular posts from this blog

C# random value from dictionary and tuple -

-
i have following code, , need random item contains string "region_1" dictionary. public static dictionary<int, tuple<string, int, currencytype>> itemarray = new dictionary<int, tuple<string, int, currencytype>>() { { 0xb3e, new tuple<string, int, currencytype>("region_1", 1500, currencytype.fame) } }; public static int generateitemid(string shopid) { var generateditem = itemarray.elementat(new random().next(0, itemarray.count)).key; } how select this? it's not possible efficiently... first create static random @ class level... prevent non-random behaviour if run query on short period of time... (it's seeded discrete clock) static random rnd = new random(); then: var item = itemarray.values .where(t => t.item1 == shopid) .orderby(_ => rnd.next()) .firstordefault()
Read more

cgi - How do I interpret URLs without extension as files rather than missing directories in nginx? -

-
so i'm trying install zoneminder , have run under nginx, has few compiled files need run using fast-cgi. these files lack extension. if file has extension, there no issue , nginx interprets file , return 404 if can't find it. if has no extension, assume it's directory , return 404 when can't find sort of index page. here have now: # security camera domain. server { listen 888; server_name mydomain.com; root /srv/http/zm; # enable php support. include php.conf; location / { index index.html index.htm index.php; } # enable cgi support. location ~ ^/cgi-bin/(.+)$ { alias /srv/cgi-bin/zm/; fastcgi_pass unix:/run/fcgiwrap.sock; fastcgi_param script_filename $document_root/$1; include fastcgi.conf; } } the idea is, under cgi-bin directory goes through fastcgi pipe. any idea on howi can fix this? upon closer inspection, realized zoneminder has 2 cgi sc...
Read more

.htaccess - htaccess convert request to clean url and add slash at the end of the url -

-
ok , searched more 4 days , more 20 posts here in stach or in websites without kind of success first here htaccess file rewriteengine on rewriterule ^([a-za-z0-9_]+)/?$ index.php?page=$1 [nc] rewriterule ^([a-za-z0-9_]+)\/([a-za-z0-9_]+)\/?$ index.php?page=$1&action=$2 [nc] i tried many codes 1 worked me can call request , works me www.example.com/pagename => www.example.com/index.php?page=pagename here questions , please provide me information "in detail" understand code well 1- how convert request automatically www.example.com/index.php?page=pagename www.example.com/pagename 2- if tried add slash @ end shows me page without images or styling mean www.example.com/pagename => works www.example.com/pagename/ => doesn't work that's :) for first part need 301 rule this: rewritecond %{the_request} /index\.php\?page=([^\s&]+) [nc] rewriterule ^ /%1? [r=301,l] for second part use absolute path in css, js, images files r...
Read more