Thread: A Stable Password Protection Program Like Facebook (Best Run in Turbo C++ 3.1)

Code:

/*:cool: Guys, This program make a file when its run. Run it and Understand it. and tell me, "can i improve in it more?*/
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
      char user[20],fltp[5]=".txt",flname[25],pswrd[35],cnfrm[35],login[35],pchek[35],c,ps,cn,lg;
      int i,j,k,l;
      FILE *usr;
      clrscr();
      gotoxy(25,23);
      textcolor(12);
      cprintf("Enter Your name:");//Note: this may be works as your username also. Name will be unique.
      scanf("%s",&user);//Scanf ko graphical bna. entry control
      strcpy(flname,user);
      strcat(flname,fltp);
      usr=fopen(flname,"r");
      if(usr==NULL)
      {
                   usr=fopen(flname,"w");
                   fprintf(usr,"Username: %s",user);
                   printf("Welcome!\nYou are a new user\nCreat your password below");
                   printf("\nEnter Password:");
                   retry:
                   j=0;
                   while((ps=getch())!=13)
                   {
                       printf("*");
                       pswrd[j]=ps;
                       j++;
                   }
                   pswrd[j]='\0';
                   printf("\nConfirm Password:");
                   k=0;
                   while((cn=getch())!=13)
                   {
                       printf("*");
                       cnfrm[k]=cn;
                       k++;
                   }
                   cnfrm[k]='\0';
                   if((strcmp(pswrd,cnfrm))==0)
                   {
                      fprintf(usr,"\nPassword: %s",cnfrm);
                      fclose(usr);
                   }
                   else
                   {
                       printf("Password didn't match! Try Again...\n");
                       printf("Enter password again:");
                       goto retry;
                   }
      }
else
{    gotoxy(25,25);
     cprintf("Password:");
     l=0;
     while((lg=getch())!=13)
     {
           printf("*");
           login[l]=lg;
           l++;
     }
     login[l]='\0';
     i=0;
      while((c=getc(usr))!= EOF)
      {
          if(c=='\n')
          {
             fseek(usr,10,1);
             while((c=getc(usr))!= EOF)
             {
                   pchek[i]=c;
                   i++;
             }
          }
      }
      pchek[i]='\0';
      if((strcmp(login,pchek))==0)
      {
         gotoxy(25,27);
         textcolor(11);
         cprintf("Welcome Back %s",user);
      }
      else
      {
          gotoxy(19,27);
          textcolor(11);
          cprintf("Wrong Password! You are not authorised");
      }
}
      getch();
}

This is just...awful:

• Don't use numbers for character constants. I have no idea what "13" represents in the getch loop.
• Don't shove all of your code into one main function, split it up.
• Learn how to do error checking to make sure that your function calls work.
• Learn about buffer overflows
• Lose all the Turbo-C ........, meaning anything from the conio.h library, cprintf(), gotoxy(), clrscr() and getch().
• Replace void main() with the shell:
  Code:

  int main (void) { return 0; }

• Get rid of all the goto spaghetti code and learn how to use a loop.
• Don't compare with a getc loop because it's very inefficient. Read everything into a buffer and strcmp().
• If you're expecting security, why are you writing the passwords to an unencrypted file?
• Learn how to indent. Your code is twice as annoying to read when it looks like a heap of mess.
• Learn to manage file handles, that means closing them when your program exits.

There's a lot more stuff but you should probably just scrap this and re-write.

Is there a reason you're doing this in c -- and Turbo c at that? You may be better off with PHP/PERL+MYSQL+a hashing algorithm.

The only thing one would have to do to break it, is to enter a user name longer than 20 characters.

Yay .. this is the "Pick on the Turbo C++ guy" day !
Thankfully.. we are having those days less frequently nowadays....it seems from the zeal of the posts here.

Originally Posted by manasij7479

Yay .. this is the "Pick on the Turbo C++ guy" day !
Thankfully.. we are having those days less frequently nowadays....it seems from the zeal of the posts here.

The guy is asking for critique and ways to improve it in the comment made at the top of the code. All people are doing is to respond to that request.

Originally Posted by Subsonics

The guy is asking for critique and ways to improve it in the comment made at the top of the code. All people are doing is to respond to that request.

your program is neither stable nor secure

O_o Facebook is stable and secure? o_O

Soma

Originally Posted by ledow

Find out yourself by running it through a vaguely-modern compiler:

tell me a new modern compiler so i can download. beacause i m a new bee in programming, so i dont know more about it.

Originally Posted by Salem

You could also try using proper words for your variable names.

yah, next time i will take care of it.

Originally Posted by Salem

Also, try writing some of the code as functions. 100+ line functions are so much harder to write / test / maintain.

i was thought so. Next time, my programmes will be in better understanding.
thanks salem.