help fast T.T

[yrhc@eht]

1how to type the code for a log in function?
descriptions: to enable librarian to log in. all the username and password of the librarian of the librarian is store in file called ''librarian_id.txt''.


*the code must include printf invalid format if user input invalid format.
*my learnt topic is ...function, making decision, repetition, text input/output, arrays and strings.
*the code should use this few topics only and not go to far.

[laserlight]

Please refer to our homework policy and edit your post accordingly.

[yrhc@eht]

Please refer to our homework policy and edit your post accordingly.

ok, laserlight, are you online now, then can you become my tutor? i will ask you step by step, i have tried myself many times, but really cant get, please. my deadline is next week.

[laserlight]

can you become my tutor?

Yes I can, but no, I will not become your tutor, unless you happen to be in my university and in a tutorial class that I happen to teach.

i will ask you step by step, i have tried myself many times, but really cant get, please.

Good to hear that you have tried. So what you should do is attempt the first step, and then post what you tried (including code) and how your attempt failed.

[yrhc@eht]

Yes I can, but no, I will not become your tutor, unless you happen to be in my university and in a tutorial class that I happen to teach.


Good to hear that you have tried. So what you should do is attempt the first step, and then post what you tried (including code) and how your attempt failed.

haha, ok ok, can we chat in msn? i am willing to learn [email protected]

[laserlight]

Use this forum.

[rasta_freak]

Wait a minute... I want laserlight as my tutor too... And i joined this forum before him !

[yrhc@eht]

T.T nvm, ok

*all the username and password of the librarian is stored in file called''Librarian_ID.txt"
* Librarian_ID.txt
--> Username (max length = 30 chars )
--> Password ( max length = 30 chars )

and below is a function to let me test is it work.

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
void librarian_module ( );

int main ( void )
{
	FILE* lib_login_pass;
	char username [ 9 ];
	char password [ 9 ];
	char lib_username [ 9 ];
	char lib_password [ 9 ];

	lib_login_pass = fopen("Librarian_ID.txt", "r" );
	if ( !lib_login_pass)
	{
		printf("Could not open file\a\n" );
		exit (101);
	}

	printf("Please enter the following:  \n");
	printf("Username: ");
	scanf(" %s", username);
	printf("Password: ");
	scanf(" %s", password);

	while ( fscanf ( lib_login_pass, " %s %s", lib_username, lib_password ) == 2 )
	{
		if  ( username == lib_username ) 
		{
			if  ( password == lib_password )
			{
				librarian_module ( );
				break;
			}
		}
		else
			printf("Wrong username or password!\n");
	}
	return 0;
}

void librarian_module ( )
{
	printf("successful\n");
	return;
}

[laserlight]

That's a step in the right direction, especially since your code is well indented with descriptive variable and function names. You also need to tell us what you expected it to do, and how does it not work.

[yrhc@eht]

it does not work, even though i type the correct username and password.

in my librarian_ID.txt:

qwertyu 1234567
abcdefg 7654321

can you tell me where is wrong or do i need use others like fgets, fget, sscanf...

[rasta_freak]

Use strcmp() instead of '==' to compare strings...

[yrhc@eht]

can you give me an example?

[rasta_freak]

can you give me an example?

if (strcmp(username, lib_username) == 0)
{
    // MATCH
}

(use strcasecmp() for case-insensitive compare)

EDIT: in case 'username' contains '\n' char, use 'n' version:

strncmp(username, lib_username, strlen(username)-1)

to compare (len-1) chars (ignore newline)

[laserlight]

(use strcasecmp() for case-insensitive compare)

Note that strcasecmp() is non-standard, though easy to implement with tolower() or toupper().

[rasta_freak]

Note that strcasecmp() is non-standard, though easy to implement with tolower() or toupper().

Do you maybe know if/where it is called "stricmp"? I know i saw it somewhere but can't remember...