Thread: C login program help

Hi guys, I'm new here and I thought of seeking some help regarding my program.

I made this program where it asks for a username and password for access. The username works well, but whenever I enter the password I programmed, it always says "access denied." Is there anyone who can help me? Here's my code and Thanks in advance!

Code:

#include <stdio.h>
#include <stdlib.h>
main()
{
char a,c;
system("cls");
printf("Enter your username: ");
scanf("%s",&a);
printf("\nEnter your password: ");
scanf("%s",&c);
if(c=='ald')
{
printf("\nAccess Granted! Welcome %s!",a);
}
else if (c=='paul')
{
printf("\nAccess Granted! Welcome %s!",a);
}
else if (c=='bil')
{
printf("\nAccess Granted! Welcome %S!",a);
}
else
printf("\nAccess Denied!");
getch(); 
return main();
}

You need to learn about C-strings.

C Strings - Cprogramming.com

- What do you think the difference between 'paul' and "paul" is?
- How many characters do you think c can store?
- What the hell is getch?

Code:

#include <stdio.h>
#include <stdlib.h>
int main()
{
    char a[20],c[20];
    //system("cls");
    printf("Enter your username: ");
    gets(a);
    printf("\nEnter your password: ");
    gets(c);
    if(strcmp(c, "ald"))
    {
        printf("\nAccess Granted! Welcome %s!",a);
    }
    else if (strcmp(c, "paul"))
    {
        printf("\nAccess Granted! Welcome %s!",a);
    }
    else if (strcmp(c, "bil"))
    {
        printf("\nAccess Granted! Welcome %s!",a);
    }
    else
        printf("\nAccess Denied!");
    //getch();
    printf("\n%s", a);

    return 0;
}

1. Did you test this version? See what happens when you try to enter an invalid password. Then read up on the return value of "strcmp()".

2. If you're using "strcmp()", you need to include string.h

3. "gets()" is dangerous - it would be safer to use "fgets()"

4. You should use more descriptive variable names - 'a' and 'c' don't tell us anything about what those variables are used for.

Also it is not helpful to post the solution for the person.

Give a man a fish......

>What the hell is getch?
TurboC allows getch with the inclusion of conio.h.

i forgot to include string standard library. I give direct answer because he is not doing homework, he is doing example. In this case, can learn by example. why gets is dangerous? fgets is dedicated to FILE string ?

Smells like homework to me, but that doesn't matter. Giving the solution robs the OP learning how to program. In my opinion you learn by doing, not by copying.

why gets is dangerous?

Because it doesn't limit the amount of characters it will receive. This can easily lead to buffer overruns.

fgets is dedicated to FILE string ?

Yes, so? The console is treated as a FILE in C. This FILE* is named stdin for the input stream and stdout for the output stream.

Jim

Originally Posted by eegii_evol

i forgot to include string standard library. I give direct answer because he is not doing homework, he is doing example. In this case, can learn by example. why gets is dangerous? fgets is dedicated to FILE string ?

Sir Your Program Also Not Working Proper I Think!!!
Because, If we Enter a Wrong Password Also it Shows the Output Like "Access Granted! Welcome"
Did You Notify that Issue

thanks for practical stuff. most of my knowledge are acquired from books. but, soon i will start to work. useful suggestion thanks

I checked before post. it was working. dunno why haha

Originally Posted by eegii_evol

I checked before post. it was working. dunno why haha

yes!Your Correct..It's Working For the Given Values...But It does n't Show the Output Like "Access Denied!" when Entering the Wrong Password