Comments by Member 13933893 (Top 17 by date)

I am tackling the problem piece by piece as recommended and sorry for all the questions. I have just made the code to open the file and read user input and write it to the file .

Could you tell me if this much is correct?

----

int main()
{

int fd;

fd = fd("user.dat", O_CREAT | O_RWDR, 0666);
if (fd == -1)
{
write(1,"There is an error opening the file",35);
}

write(1,"Enter the username",18);


char username[USERNAME_SIZE];
char c;
int count = 0;
do
{
read(0, &c, 1);
if (c == '\n')
break;
username[count++] = c;
}
while (count < USERNAME_SIZE - 1);
username[count] = 0;

write(fd,username,USERNAME_SIZE);

char kbinput[KBINPUT_SIZE]; // The array in which the complete string is stored.
char c; // The single character it is reading
int count = 0;
do
{
read(0, &c, 1); // Reading 1 alphabet into variable c
if (c == '\n') // When you press enter, exit the loop.
break;
kbinput[count++] = c; // increments the array to the next position so as to take the next alphabet?
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;

I do not understand the last 2 lines, can you please clarify that for me

Hi Jochen , I am able to understand what you are trying to say but I am not sure of how to add it in my program , I have tried to search for references but I am having a lot of difficulty in achieiving this, hoping you could provide me further guidance and clarity on my code

#include <stdio.h>


int main()
{
int fd;
char username;
char kbinput[KBINPUT_SIZE];
char kbinputpassone[KBINPUTPASSONE_SIZE];
char kbinputpasstwo[KBINPUTPASSTWO_SIZE];
char passwordone;
char passwordtwo;
int count = 0;
int result;
int ret;


fd = open("test.txt", O_CREAT | O_RDWR,0666);
if(fd == -1)
{
printf("Error!");
exit(1);
}

write(1,"Enter the username",18);
do
{
read(0, &username, 1);
if (username == '\n')
break;
kbinput[count++] = username;
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;
write(fd,username,10);


write(1,"Enter the password",18);
do
{
read(0, &passwordone, 1);
if (passwordone == '\n')
break;
kbinputpassone[count++] = passwordone;
}
while (count < KBINPUTPASSONE_SIZE - 1);
kbinputpassone[count] = 0;


write(1,"Enter the password again",25);
do
{
read(0, &passwordtwo, 1);
if (passwordtwo == '\n')
break;
kbinputpasstwo[count++] = passwordtwo;
}
while (count < KBINPUTPASSTWO_SIZE - 1);
kbinputpasstwo[count] = 0;


result = memcmp(passwordone,passwordtwo,10)
if (result == 0)
write(1,"Password length is equal",25);
else
write(1,"Password lengths do not match",30);


write(1,"The Passwords match",20);
write(fd, passwordone, 15);

return 0;

}

As suggested , I have implemented a check to see if the array lengths match, requesting you to check if the same is correct or not and if possible guide further.

#include <stdio.h>


int main()
{
int fd;
char username;
char kbinput[KBINPUT_SIZE];
char kbinputpassone[KBINPUTPASSONE_SIZE];
char kbinputpasstwo[KBINPUTPASSTWO_SIZE];
char passwordone;
char passwordtwo;
int count = 0;
int result;
int ret;


fd = open("test.txt", O_CREAT | O_RDWR,0666);
if(fd == -1)
{
printf("Error!");
exit(1);
}

write(1,"Enter the username",18);
do
{
read(0, &username, 1);
if (username == '\n')
break;
kbinput[count++] = username;
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;
write(fd,username,10);


write(1,"Enter the password",18);
do
{
read(0, &passwordone, 1);
if (passwordone == '\n')
break;
kbinputpassone[count++] = passwordone;
}
while (count < KBINPUTPASSONE_SIZE - 1);
kbinputpassone[count] = 0;


write(1,"Enter the password again",25);
do
{
read(0, &passwordtwo, 1);
if (passwordtwo == '\n')
break;
kbinputpasstwo[count++] = passwordtwo;
}
while (count < KBINPUTPASSTWO_SIZE - 1);
kbinputpasstwo[count] = 0;


result = memcmp(passwordone,passwordtwo,10)
if (result == 0)
write(1,"Password length is equal",25);
else
write(1,"Password lengths do not match",30);


write(1,"The Passwords match",20);
write(fd, passwordone, 15);

return 0;

}

@User-2223753 , Since I am very new to codign, thank you for all your inputs , as suggested, I have created 3 different arrays( kbinput, kbinputpassone and kbinputpasstwo) . However, I am still not sure where the password matching is happening before writing to the file .

Following is what I have done until now as per your suggestions :
---------

#include <stdio.h>


int main()
{
int fd;
char username;
char kbinput[KBINPUT_SIZE];
char kbinputpassone[KBINPUTPASSONE_SIZE];
char kbinputpasstwo[KBINPUTPASSTWO_SIZE];
char passwordone;
char passwordtwo;
int count = 0;

int ret;
fd = open("test.txt", O_CREAT | O_RDWR,0666);
if(fd == -1)
{
printf("Error!");
exit(1);
}

write(1,"Enter the username",18);
do
{
read(0, &username, 1);
if (username == '\n')
break;
kbinput[count++] = username;
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;
write(fd,username,10);


write(1,"Enter the password",18);
do
{
read(0, &passwordone, 1);
if (passwordone == '\n')
break;
kbinputpassone[count++] = passwordone;
}
while (count < KBINPUTPASSONE_SIZE - 1);
kbinputpassone[count] = 0;


write(1,"Enter the password again",25);
do
{
read(0, &passwordtwo, 1);
if (passwordtwo == '\n')
break;
kbinputpasstwo[count++] = passwordtwo;
}
while (count < KBINPUTPASSTWO_SIZE - 1);
kbinputpasstwo[count] = 0;


write(1,"The Passwords match",20);
write(fd, passwordone, 15);

return 0;

}

------------------------------------------
Would like to know where the comparison and check for matching the password is happening and if its not happening, could you please add that for me and correct my program. I will go through it and try to understand everything mentioned by you and use it for future.

@User-2223753 | Jochen, I have done as suggested , changed a few variables , requesting you to go through and let me know if its alright. I am not sure where the comparison is happening .

A small request if you could modify my program and show me where I am going wrong .

#include <stdio.h>


int main()
{
int fd;
char username;
char kbinput[KBINPUT_SIZE];
char passwordone;
char passwordtwo;
int count = 0;

int ret;
fd = open("test.text", O_CREAT | O_RDWR,0666);
if(fptr == -1)
{
printf("Error!");
exit(1);
}

write(1,"Enter the username",18);
do
{
read(0, &username, 1);
if (username == '\n')
break;
kbinput[count++] = username;
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;
write(fd,username,10));


write(1,"Enter the password",18);
do
{
read(0, &passwordone, 1);
if (passwordone == '\n')
break;
kbinput[count++] = passwordone;
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;


write(1,"Enter the password again",25);
do
{
read(0, &passwordtwo, 1);
if (passwordtwo == '\n')
break;
kbinput[count++] = passwordtwo;
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;


write(1,"The Passwords match",20);
write(fd, passwordone, 15);

return 0;

}

Would request your further assistance, the loop is basically reading input from the keyboard and storing into character C until the user presses Enter key.

I am not able to get the second part as to what that is doing .

Also, could you please help me implement the check in my program .
This is what I have done and I do not know if its correct or not .

#include <stdio.h>


int main()
{
int fd;
char username[10];
char kbinput[KBINPUT_SIZE];
char c;
int count = 0;

int ret;
fd = open("test.text", O_CREAT | O_RDWR,0666);
if(fptr == -1)
{
printf("Error!");
exit(1);
}

write(1,"Enter the username",18);
ret = read(0, username, 10);
write(fd,username,10));


do
{
read(0, &c, 1);
if (c == '\n')
break;
kbinput[count++] = c;
}
while (count < KBINPUT_SIZE - 1);
kbinput[count] = 0;
write(1,"The Passwords match",20);
write(fd, passwordone, 15);

return 0;

}


@User-2223753 | Jochen

Having gone through your suggestions and details.

This is what I have got till now :
#include <stdio.h>


int main()
{
int fd;
char username[10];
char passwordone[15];
char passwordtwo[15];

int ret;
fd = open("test.text", O_CREAT | O_RDWR,0666);
if(fptr == -1)
{
printf("Error!");
exit(1);
}

write(1,"Enter the username",18);
ret = read(0, username, 10);
write(fd,username,10));

while (1)
{
write(1,"Enter the password",18);
read(0, passwordone, 15);

write(1,"Enter the password again",25);
read(0, passwordtwo, 15);

if ( strcmp(passwordone, passwordtwo) == 0)
break;

write(1,"The passwords do not match",28);
}

write(1,"The Passwords match",20);
write(fd, passwordone, 15);

return 0;

}


Could you let me know if this is correct , if not could you help me and point out where the mistakes are .
Highly appreciate your help
@User-2223753 | Jochen

#include <stdio.h>


int main()
{
int fd;
char username[10];
int ret;

fd = open("test.text", O_CREAT | O_RDWR,0666);
if(fptr == -1)
{
printf("Error!");
exit(1);
}

printf("Enter your username");
ret = read(0, username, 10);
write(fd,username,strlen(username));



@User-2223753 | Jochen, this is what I have till now, please can you guide me further.
Let me know if I am on the right track and how to exactly proceed with comparing two passwords. if any sample code could be provided.

Hello CPallini,

Thank you for the same. However I have some few doubts.

While I compile the same , I get the warning that "gets" is a dangerous function and to switch it to "fgets" wherever gets is used.

However on doing so and recompiling, I am receiving further errors now .

I am not sure if the arguements that is only the variable passed is sufficient.

What other parameters need to be passed on ?

Reference of the error :
test.c:22:3: error: too few arguments to function ‘fgets’
fgets(username);
^~~~~
In file included from test.c:1:0:
/usr/include/stdio.h:564:14: note: declared here
extern char *fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
^~~~~
test.c:29:5: error: too few arguments to function ‘fgets’
fgets(passwordone);
^~~~~
In file included from test.c:1:0:
/usr/include/stdio.h:564:14: note: declared here
extern char *fgets (char *__restrict __s, int __n, FILE *__restrict __stream)

Hi CPallini and Nelek.

Thank you for your valuable suggestions .

I am writing this program as a beginner and highly appreciate all your inputs .

After having gone through your suggestion and implementing the same , I am able to write the password only when they match. However I am not able to understand the concept of the while loop . If one of you guys coudl help me understand the same and give me a small example of an implementation it would be great.

This is what I have got till now
#include <stdio.h>
#include <stdlib.h> /* For exit() function */
int main()
{
char username[1000];
char passwordone[1000];
char passwordtwo[1000];

FILE *fptr;

fptr = fopen("program.txt", "w");
if(fptr == NULL)
{
printf("Error!");
exit(1);
}

printf("Enter your username\n");
gets(username);

fprintf(fptr,"%s", username);

printf("Enter your password\n");
gets(passwordone);

printf("Enter your password again\n");
gets(passwordtwo);


if (strcmp(passwordone,passwordtwo)==0)
{
printf("The Passwords match");
fprintf(fptr,"%s", passwordone);
}
else
{
printf("The passwords do not match");
}
fclose(fptr);

return 0;
}