Thread: help

the program asks the id and password of the user, then compares it to the list of IDs and Passwords in a ready file..i think theres something wrong with the while loop.when i run the program, it stops working after i enter the id and password.it doesnt enter the while loop.

Code:

            printf("\nKULLANICI ISIM: ");
            scanf("%s",&tempid);
            printf("\nKULLANICI SIFRE");
            scanf("%s",&temppass);
            while((c=getc(fidpasstud))==tempid&&(d=getc(fidpasstud))==temppass)
            {......

I did what you said, and the problem is the same.The program ends without showing the phrase "Correct id and password".I already have a file containing Ids and passwords.

Code:

#include <stdio.h>
#include <stdlib.h>
FILE *filename;
int main()
{
         char tempid[10],tempass[10],c,d;
         printf("enter ID:");
         scanf("%s",&tempid);
         printf("enter PASS:");
         scanf("%s",tempass);
         filename=fopen("ids.txt","r");
         while((c=getc(filename))==tempid&&(d=getc(filename))==tempass)
         {
                    printf("Correct ID and password.");
         }
         fclose(filename);
         return 0;
}

i changed &tempid, but still nothing...

Of course. What about the other two paragraphs? You need to change you approach IMO. If the username is "user" and your password is "pass" you need to store them like this with your current method: "upsaesrs"

After you compare characters, which means dereferencing tempid and tempass.

It would be better to do this separately instead and compare the entire string with strcmp.

i'm pretty new to C so dont get mad (u can laugh if you want)...but what you just typed sounds like giberish..i'm sorry..can u use smaller words?

Getting at the characters requires something like this: tempid[0], tempid[1] and so on to get the first and second character. But you read one character and expect that to belong to username and the second character to belong to password.

Read password first, then username. Not both at the same time if you want to use your current method.

The best is probably to read the password and user name separately. Then compare them in a separate step, you can use strcmp() for that, it takes two strings as argument and returns 0 if they are the same. Beware of the newline character ('\n') however which might be present in your file.

ok.i thought meant that the first character of the username is tempid[0], second character is tempid[2] and so on.

in the file, there's going to be many IDs and Passwords.What i was thinking was that getc returns one character at a time and it will compare that character with the characters if the username..

Code:

#include <stdio.h>
#include <stdlib.h>
FILE *filename;
int main()
{
    char tempid[10],tempass[10],c[10];
    printf("enter ID:");
    scanf("%s",tempid);
    printf("enter PASS:");
    scanf("%s",tempass);
    filename=fopen("ids.txt","r");
    while(getc(filename)!='\n')
    {
        c=getc(filename);
        if(strcmp(c,tempid)==0)
        printf("Correct ID and password.");
    }
    fclose(filename);
    return 0;
}

something like this?