Thread: How do i create this code into a function?

Hi Guys,

so sorry to create a new thread.

But just wondering...

how do i create a function of checkpw() with this bunch of codes...

Code:

   while( fgets(line_buffer,sizeof(line_buffer),fpassword) != NULL )  /* read from file while still data available */
     {

          char ftemp[20], fpass[20], fuser[20];

          sscanf(line_buffer,"%s %s %s",&ftemp,&fpass,&fuser);


          if (strcmp(user, fuser) == 0) /* OK, found the username the user inputted */
          {
             printf("\n\nUsername Correct\n");

             if (strcmp(pass, fpass) == 0)
             {
		         printf("User authorized");
                 getchar();
                 exit(1);
             }
          }
     }
    printf("\n\nInvalid Username or Password");
    fclose(fpassword);
    getchar();

Originally Posted by Salem

Well first you decide what would be the useful parameters of the function (say the password filename), and what can be just local variables (say ftemp).

Then you decide that exit(1) is a bad thing to do, and invent some status returns for the function, say
- pass
- fail
- file not found

> sscanf(line_buffer,"%s %s %s",&ftemp,&fpass,&fuser);
There's no need (it's also wrong) to use & when the target is a char array, and the format is %s. It's one of the few exceptions.
Also checking the return result is a good idea as well.
Using a field width in the conversion makes it even better.

i did this and doesn't work why....

Code:

......

checkpw();

......

char checkpw(char pass, char fpass)
{
      if(strcmp(pass, fpass) == 0)
      {
		         printf("User authorized");
                 getchar();
                 exit(1);
      }
      printf("\n\nInvalid Username or Password");
      getchar();
      exit(1);
}

how come doesn't work.....

also it might be safer putting either the function ahead of your main or at least putting a function prototype up there, but i guess that depends on your compiler

depending on the intended length of passwords and the purpose you might also consider converting the parameter passing to pointer passing, since your not actually operating on either value

Code:

char *pass;
char *fpass;

...

checkpw(pass, fpass);

...
char checkpw(char *pass, char *fpass)
{
...
}