Retrieving Multiple inputs with fgets?

i want to retrieve 6 lines of text, from a user. I've tried the following:
char userInput[160];

fgets(userInput, 160, stdin);
>some text inputted1
fgets(userInput, 160, stdin);
>some text inputted2
fgets(userInput, 160, stdin);
>some text inputted3
fgets(userInput, 160, stdin);
>some text inputted4
fgets(userInput, 160, stdin);
>some text inputted5
fgets(userInput, 160, stdin);
>some text inputted6

for some reason when i use printf("%s", userInput); it prints the latest inputted text and not the previously entered ones :confused:

It doesn't copy one line onto the end of another. It simply reuses the buffer you keep passing it. If you want multiple lines stored, copy them to another buffer, and concatenate them. (See: strcat)


Quzah.

strcat looks like it'll do the job but i was just intrested, can this be done with fgets only?

Maybe

Code:

---

char userInput[6][160];
fgets(userInput[0], 160, stdin);
fgets(userInput[1], 160, stdin);

---

Segmentation fault :|

and strcat seems to work with a fixed string but it won't work with stdin

Quote:

---

Originally Posted by Axel

Segmentation fault :|

---

With what code? Salem's example is fine.

Quote:

---

Originally Posted by Axel

and strcat seems to work with a fixed string but it won't work with stdin

---

With what code? stdin is a file stream alias. It's not a string.

You can't just say "it doesn't work" without showing your code. Well you can, but you're not going to get any help that way.


Quzah.

This is an answer.

Correct, it's as useless as your question.

Quote:

---

Originally Posted by quzah

With what code? Salem's example is fine.With what code? stdin is a file stream alias. It's not a string.

You can't just say "it doesn't work" without showing your code. Well you can, but you're not going to get any help that way.


Quzah.

---

I don't think strcpy will work with what i'm trying to do it works fine with fixed strings but what about entered text from the user?

Also:

Code:

---

char userInput[6][160];

---

that doesn't seem to work it just gives me a segmentation error. What i've did is create 6, 1 dimensional arrays representing the rows so i used gets as follows:


fgets(text1, 10, stdin); .... text7

and when i print it, it works :-) it's not really an ideal way of doing it
but i still can't figure how to fill a 2-d array using fgets without overwriting the buffer when i use fgets mulitple times.

Quote:

---

Originally Posted by Axel

but i still can't figure how to fill a 2-d array using fgets without overwriting the buffer when i use fgets mulitple times.

---

Code:

---

{
    int line;
    char userInput[6][160];
    for (line = 0 ; line < 6; line++)
        fgets(userInput[line], 160, stdin);

    for (line = 0 ; line < 6; line++)
        printf("line %d: %s\n", line, userInput[line]);
}

---

See how hard that was? Now if you had posted more than a single line of code, we could have looked at your example and told you what was wrong. See cwr's code? Let's pretend it was yours, and you posted it. Let's also pretend it's incorrect. Let's pretend you now said something like: "I'm trying to fill 'userInput' with six lines of input, but [whatever.... it stops after line 1, it doesn't print them right, whatever it is]."


See how much better that would have been than just sticking one line of code and saying "that doesn't seem to work it just gives me a segmentation error."


I hate having to teach people how to ask questions.


Quzah.

thanks cwr. There's just one problem though printf("%c", userInput[line1][line2]);
i have a for loop which prints out every character in the column and goes to the next row and prints out the next column etc...
as soon as it gets to the last element in the column it prints out a space.
i.e.

userInput[0][0] = 'H';
userInput[0][1] = 'e';
userInput[0][2] = 'l';
userInput[0][3] = 'l';
userInput[0][4] = 'o';
userInput[0][5] = ' '; // <--------- annoying space.

Is there anyway to discard it? I've tried using != '\0' but it doesn't seem to help.

But i'm gussing the main problem is with the original code, it doesn't discard the spaces by check if it's not '\0'.

I've tried

Code:

---



    for (row = 0 ; line < 6; row++)
        fgets(userInput[row][col], 160, stdin);

---

but i just get

warning: passing arg 1 of `fgets' makes pointer from integer without a cast


It's a bit tricky because cwr's code, seems to fill the columns, as soon as somethings entered it adds the space to the end and goes to the next row, i can't check if an element inside a column has a space with another for loop.


Also, quzah sorry about my my previous post... in future i'll try to be more specific.

> warning: passing arg 1 of `fgets' makes pointer from integer without a cast
Well yeah, because userInput[row][col] is a single char, and fgets needs an array of them

i tried referecing a pointer (userInput)

fgets(*userInput, 160, stdin);

but it doesn't seem to fill the array properly.

You need to read a book.
http://www.amazon.com/exec/obidos/se...0&Go.y=0&Go=Go

> fgets(*userInput, 160, stdin);
You have a splendid nack of trying every single possible combination except the right ones told to you by everyone else.

Are you a troll?

Quote:

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You have a splendid nack of trying every single possible combination except the right ones told to you by everyone else.

---

My original question is yet to be answered. I still can't fill a 2-d array with fgets :| well, i can sort of but i want to manipluate the columns as it's filling. I tried using a pointer that worked, but the array wasn't being filled properly, tried the actual index number of the element i.e. array[0][0] that didn't work. What confuses me is that array[line] works but array array[line][line2] does not.

Really, i don't mean to be of any annoyance and mostly all the stuff i use comes from books or online.

seems as though userInput[line1][line2] works after all. i'm going to try filling the array using the line2(column) and discard the spaces at the end. I'll post back with the outcome soon.

.. ok maybe not:
passing arg 1 of `fgets' makes pointer from integer without a cast
userInput[line1][line2]

both userInput[line]
userInput[line2] work perfectly but i don't want the row :| i want a reference to the column

any ideas?

Code:

---

userInput[0][0] = 'H';
userInput[0][1] = 'e';
userInput[0][2] = 'l';
userInput[0][3] = 'l';
userInput[0][4] = 'o';
userInput[0][5] = ' '; // The ony problem i see is the newline that will get included using fgets

---

to solve above problem, do this

Code:

---

char *n;
n = strchr( userInput[0], '\n' );
*n = '\0';

---

and also why woud you print the characters one by one when you can print is as a whole

Code:

---

printf("%c", userInput[line1][line2]); // WTF!!  :eek:

  

just do:
printf( "%s", userInput[line1] );

       

Code:

       

---

    for (row = 0 ; line < 6; row++)
       fgets(userInput[row][col], 160, stdin); // this is wrong
should be fgets(userInput[row], sizeof( userInput[row] ), stdin);

---

---

I suggest that you go and read the replies to this thread before posting some more questions. Your too excited :)

Compile, run and study this and see if it helps you:

Code:

---

#include <stdio.h>
#include <ctype.h>

int main(void)
{
  char userInput[2][20];
  int i, j;
 
  for (i = 0; i < 2; i++)
  {
    sprintf (userInput[i], "This is line %d", i);
  }
 
  printf ("Printing complete array:\n");
 
  for (i = 0; i < 2; i++)
  {
    for (j = 0; j < 20; j++)
    {
      printf ("userInput[%d][%2d] = '%c'\n", 
              i, j, isprint(userInput[i][j]) ? userInput[i][j] : '.' );
    }
  }
 
  printf ("Printing only populated area of array:\n");
 
  for (i = 0; i < 2; i++)
  {
    for (j = 0; j < 20 && userInput[i][j] != '\0'; j++)
    {
      printf ("userInput[%d][%2d] = '%c'\n", 
              i, j, isprint(userInput[i][j]) ? userInput[i][j] : '.' );
    }
  }
 
  printf ("Printing as strings:\n");
 
  for (i = 0; i < 2; i++)
  {
    puts (userInput[i]);
  }
 
  return(0);
}


/*
 Output
 
Printing complete array:
userInput[0][ 0] = 'T'
userInput[0][ 1] = 'h'
userInput[0][ 2] = 'i'
userInput[0][ 3] = 's'
userInput[0][ 4] = ' '
userInput[0][ 5] = 'i'
userInput[0][ 6] = 's'
userInput[0][ 7] = ' '
userInput[0][ 8] = 'l'
userInput[0][ 9] = 'i'
userInput[0][10] = 'n'
userInput[0][11] = 'e'
userInput[0][12] = ' '
userInput[0][13] = '0'
userInput[0][14] = '.'
userInput[0][15] = '.'
userInput[0][16] = '.'
userInput[0][17] = '.'
userInput[0][18] = '@'
userInput[0][19] = '.'
userInput[1][ 0] = 'T'
userInput[1][ 1] = 'h'
userInput[1][ 2] = 'i'
userInput[1][ 3] = 's'
userInput[1][ 4] = ' '
userInput[1][ 5] = 'i'
userInput[1][ 6] = 's'
userInput[1][ 7] = ' '
userInput[1][ 8] = 'l'
userInput[1][ 9] = 'i'
userInput[1][10] = 'n'
userInput[1][11] = 'e'
userInput[1][12] = ' '
userInput[1][13] = '1'
userInput[1][14] = '.'
userInput[1][15] = '.'
userInput[1][16] = 'H'
userInput[1][17] = '.'
userInput[1][18] = '@'
userInput[1][19] = '.'
Printing only populated area of array:
userInput[0][ 0] = 'T'
userInput[0][ 1] = 'h'
userInput[0][ 2] = 'i'
userInput[0][ 3] = 's'
userInput[0][ 4] = ' '
userInput[0][ 5] = 'i'
userInput[0][ 6] = 's'
userInput[0][ 7] = ' '
userInput[0][ 8] = 'l'
userInput[0][ 9] = 'i'
userInput[0][10] = 'n'
userInput[0][11] = 'e'
userInput[0][12] = ' '
userInput[0][13] = '0'
userInput[1][ 0] = 'T'
userInput[1][ 1] = 'h'
userInput[1][ 2] = 'i'
userInput[1][ 3] = 's'
userInput[1][ 4] = ' '
userInput[1][ 5] = 'i'
userInput[1][ 6] = 's'
userInput[1][ 7] = ' '
userInput[1][ 8] = 'l'
userInput[1][ 9] = 'i'
userInput[1][10] = 'n'
userInput[1][11] = 'e'
userInput[1][12] = ' '
userInput[1][13] = '1'
Printing as strings:
This is line 0
This is line 1
*/

---

Some notes:

- When printing the entire array, the areas after the actual data are filled with unpredicatable data. That's the nature of uninitialised memory.

- In my second print loop, I said "print populated area". I have neglected to print the \0 terminator for each string, which is technically part of the "populated area". Minor technicallity, didn't want to get picked up on it! ;)

- I used isprint() to determine if a character is printable before attempting to print it. That way, any unprintable characters will be displayed as a dot instead of garbage.

- My data is simulated input, what out for the \n that fgets() may add to the end of the userInput string.

Quote:

---

Originally Posted by Hammer

Compile, run and study this and see if it helps you:

---

Thanks for that. Although it did clear a few things up i already know the basics of 2-d arrays. The problem is with inputted text.

In the populated area you have:

for (j = 0; j < 20 && userInput[i][j] != '\0'; j++)

that's what i'm stuck on, i can't check if a column has a space. cwr's code only accepts rows as the parameter i can't get it to accept a column reference to discard spaces using a for loop. Where as in your code you're checking.

But with your code it kind of gives me an idea, maybe i should copy it [the userInput array] into a new array and run a for loop to discard the spaces at the end like what you have done and instead of printing it, i'll just copy it into a new array without the spaces? I'll give that a go and post back. This problem is really annoying.

also loko, the following:

Code:

---


char *n;
n = strchr( userInput[0], '\n' );
*n = '\0';

---

doesn't seem to do anything. When printed, the array is exactly the same so i tried tinkering with it:

Code:

---


char *n;
n = strchr( userInput[row], '\n' );
*n = '\0';

---

gives me the dreaded segmentation fault

I'm guessing it's because

Code:

---


  for (line = 0 ; line < 8; userInput++)
      fgets(userInput[line], 160, stdin);

  char *n;
n = strchr( userInput[0], '\n' );
*n = '\0';

---

somehow in the for loop it stops working

Also, a question why have you choosen to put a new line in userInput[0]? and not the last column in the row?

ok, copying the userInput array into a 'clean' array with no spaces didn't work. The same thing happens when printing out the array even if you include a for loop saying i don't want '\0'

Code:

---


    for (line = 0 ; line < 6; line++)
      fgets(userInput[line], 160, stdin);


int i, j;

 for (i = 0; i < 6; i++)
  {
    for (j = 0; j < 160 && userInput[i][j] != '\0'; j++)
    {
      printf("\n%s", "Column "); printf("%d ", j); printf("%s", "has -=> ");
      printf ("%c", userInput[i][j]);
    }
  }

---

result:


Column 0 has -=> h
Column 1 has -=> e
Column 2 has -=> l
Column 3 has -=> l
Column 4 has -=> o
Column 5 has -=>

Column 0 has -=> h
Column 1 has -=> e
Column 2 has -=> l
Column 3 has -=> l
Column 4 has -=> o
Column 5 has -=>

Column 0 has -=> h
Column 1 has -=> e
Column 2 has -=> l
Column 3 has -=> l
Column 4 has -=> o
Column 5 has -=>

Column 0 has -=> h
Column 1 has -=> e
Column 2 has -=> l
Column 3 has -=> l
Column 4 has -=> o
Column 5 has -=>

Column 0 has -=> h
Column 1 has -=> e
Column 2 has -=> l
Column 3 has -=> l
Column 4 has -=> o
Column 5 has -=>

Column 0 has -=> h
Column 1 has -=> e
Column 2 has -=> l
Column 3 has -=> l
Column 4 has -=> o
Column 5 has -=>




... bit strange don't you think? EVEN after i specifically said in the inner for loop to not include spaces.

It's not a space. It's a newline. You're using fgets, which includes the newline in the input. Try printing the decimal value of the character instead of the character representation of it. (%d)


Quzah.

actually, i tried what you suggested:
which gave me the following,

Code:

---


Column 0 has -=> 97
Column 1 has -=> 100
Column 2 has -=> 97
Column 3 has -=> 100
Column 4 has -=> 115
Column 5 has -=> 10
Column 0 has -=> 97
Column 1 has -=> 100
Column 2 has -=> 115
Column 3 has -=> 10
Column 0 has -=> 97
Column 1 has -=> 100
Column 2 has -=> 115
Column 3 has -=> 10
Column 0 has -=> 97
Column 1 has -=> 100
Column 2 has -=> 115
Column 3 has -=> 10
Column 0 has -=> 97
Column 1 has -=> 100
Column 2 has -=> 115
Column 3 has -=> 10
Column 0 has -=> 97
Column 1 has -=> 100
Column 2 has -=> 115
Column 3 has -=> 97
Column 4 has -=> 100
Column 5 has -=> 115

---

i modified this bit:

Code:

---



printf ("%d", userInput[i][j]);

---

but your post gave me an idea, i put != '\n' in the for loop and it works now thanks :-)

>>i put != '\n' in the for loop and it works now thanks
Just remember, fgets() won't always put a \n at the end of the string.