how to read strings?

**happyclown** · 01-17-2009

Here's a bit of my code:

Code:

  
struct data {
        int month, day, year, hour, minute, number;
        char string1[2];
        char string2[FILENAMELENGTH];
        char stringstorage[LINELENGTH];  /* Used to store strings from file */
    } LineData[NUMBEROFFILES];

while( (fgets(LineData[count].stringstorage, LINELENGTH , openfile) != NULL) && (count < NUMBEROFFILES) )
    {
        /* code to process string */
        count++;
        lastfilecount = count;
    }

I would like to read the strings in the array(or even a pointer), and seperate the data in the string.

I am thinking something similar to:

Code:

fscanf(openfile, "%d/%d/%d %d:%d %s %d %s", &LineData[count].month, &LineData[count].day,
                               &LineData[count].year, &LineData[count].hour, &LineData[count].minute,
                              LineData[count].string1, &LineData[count].number, &LineData[count].string2);

but using the array "LineData[count].stringstorage" as a source, instead of using a file.

I know how to read strings from keyboard input(gets), and files(fscanf), but strangely enough, I don't know how to read strings which sit in an array, or a pointer. And my C book isn't of any help.

I did a search in the forums, but can't find anything that I could use. Maybe because I am not using the right keywords.

Thanks.

**Adak** · 01-17-2009

One way to print a string in an array of char's would be to loop through the array, and print it char by char, with putchar(index).

Another way would be:

Code:

printf("%s", array);

Or for a 2 dimensional array:

Code:

printf("%s", array[indexYouWant]);

This requires both strings to have an end of string marker on them, to work right.

This just uses the fact that the array name points to the base of the array itself (or the row, in the second case).

**happyclown** · 01-17-2009

Thanks Adak.

I don't have a problem with reading and printing arrays or pointers.

This may be a better wording of what I want to achieve:

I would like to read("process") a string, and the string does not come from the keyboard(stdin), or a file(stream). The string sits in an array, or a pointer.

My problem is that I don't know how to manipulate a string, and these string functions don't help.

EDIT: Here's the contents of a file that I want to read:

12/16/2008 10:21 AM 969 bobthebuilder.html
08/14/2008 06:13 AM 10,261 purplebarney.html
08/14/2008 06:08 AM 12,083 mrpotatohead.html
08/09/2008 05:10 PM 4,076 spongebob.html
08/09/2008 05:41 PM 3,531 thewiggles.html
12/06/2008 03:04 PM 1,016 lindsaylohan.html

And here's attempt, which clearly does not work.

Code:

#include <stdlib.h>
#include <stdio.h>

#define NUMBEROFFILES 1000
#define FILENAMELENGTH 40
#define LINELENGTH 100

int main( void )
{
    int count, lastfilecount;
    FILE *openfile;

    struct data {
        int month, day, year, hour, minute, number;
        char string1[2];
        char string2[FILENAMELENGTH];
        char stringstorage[LINELENGTH];  /* Used to store strings from file */
    } LineData[NUMBEROFFILES];

    /* Test to see that the file "directorylisting.txt" can be opened for reading. */

    if( (openfile = fopen("directorylisting1.txt", "rt")) == NULL)
    {
        perror("\ndirectorylisting1.txt");
        exit( EXIT_FAILURE );
    }

    /* Read one line at a time into structure */

    count = 0;

    while( (fgets(LineData[count].stringstorage, LINELENGTH , openfile) != NULL)
                                                        && (count < NUMBEROFFILES) )
    {
        fscanf(openfile, "%d/%d/%d %d:%d %s %d %s", &LineData[count].month, &LineData[count].day,
                            &LineData[count].year, &LineData[count].hour, &LineData[count].minute,
                            LineData[count].string1, &LineData[count].number, &LineData[count].string2);  

        count++;
        lastfilecount = count;
    }

    fclose(openfile);

    /* Print the structures */

    for( count = 0; count < lastfilecount; count++)
    {
        printf("%d/%d/%d %d:%d %s %d %s\n", LineData[count].month, LineData[count].day, LineData[count].year,
              LineData[count].hour, LineData[count].minute, LineData[count].string1,
          LineData[count].number, LineData[count].string2);
    }

    return 0;
}

The code in red should not be there, but it's just to give people an idea of what I want to achieve.

**MK27** · 01-17-2009

sscanf

**Adak** · 01-18-2009

This is what I was suggesting:

Code:

#include <stdio.h>

char array[10][20] = {
 { "George" },
 { "Giorgina" },
 { "Gillermo" },
 { "Gilliam" },
 { "Gladstone"},
 { "Goodman" },
 };

int main(void)
   {
   int i;
   for(i = 0; i < 10 ; i++)
      printf("%s \n", array[i]);

   printf("\n\n\t   Program Complete - Press Any Key to Continue ");
   i = getchar();
   return 0;  
   }

In your case it might be linedata[i].string1 and linedata[i].string2, instead of array[i]

**happyclown** · 01-18-2009

Originally Posted by MK27

sscanf

This was the function that I was looking for, thanks.

But there's a slight problem that I'm having.

Code:

#include <stdlib.h>
#include <stdio.h>

#define NUMBEROFFILES 1000
#define FILENAMELENGTH 40
#define LINELENGTH 100

int main( void )
{
    int count, lastfilecount;
    FILE *openfile;

    struct data {
        int month, day, year, hour, minute, number;
        char string1[2+1];
        char string2[FILENAMELENGTH];
        char stringstorage[LINELENGTH];  /* Used to store strings from file */
    } LineData[NUMBEROFFILES];

    /* Test to see that the file "directorylisting.txt" can be opened for reading. */

    if( (openfile = fopen("directorylisting1.txt", "rt")) == NULL)
    {
        perror("\ndirectorylisting1.txt");
        exit( EXIT_FAILURE );
    }

    /* Read one line at a time into structure */

    count = 0;

    while( (fgets(LineData[count].stringstorage, LINELENGTH , openfile) != NULL) && (count < NUMBEROFFILES) )

    {
        sscanf(LineData[count].stringstorage, "%d/%d/%d %d:%d %s %d %s", &LineData[count].month, &LineData[count].day,
                          &LineData[count].year, &LineData[count].hour, &LineData[count].minute,
                         LineData[count].string1, &LineData[count].number, &LineData[count].string2);

        count++;
        lastfilecount = count;
    }

    fclose(openfile);

    /* Print the structures */

    for( count = 0; count < lastfilecount; count++)
    {
        printf("%d/%d/%d %d:%d %s %d %s\n", LineData[count].month, LineData[count].day,

LineData[count].year,
 LineData[count].hour, LineData[count].minute, LineData[count].string1,
                          LineData[count].number, LineData[count].string2);
    }

    return 0;
}

This is what I'm trying to read:

12/16/2008 10:21 AM 969 bobthebuilder.html
08/14/2008 06:13 AM 10,261 purplebarney.html
08/14/2008 06:08 AM 12,083 mrpotatohead.html
08/09/2008 05:10 PM 4,076 spongebob.html
08/09/2008 05:41 PM 3,531 thewiggles.html
12/06/2008 03:04 PM 1,016 lindsaylohan.html

This is the output:

12/16/2008 10:21 AM 969 bobthebuilder.html
8/14/2008 6:13 AM 10 ,261
8/14/2008 6:8 AM 12 ,083
8/9/2008 5:10 PM 4 ,076
8/9/2008 5:41 PM 3 ,531
12/6/2008 3:4 PM 1 ,016
0/0/0 0:0 0

The comma in the numbers are causing the rest of the line to be chopped off.

I'll try to figure this one out, and will post back here in a few days if I still need help.

Thanks for everybody's help.

**happyclown** · 01-18-2009

Ok, I think I might be heading in the right direction.

Code:

sscanf(LineData[count].stringstorage, "%d%/%d/%d %d:%d %s %d,%d %s", &LineData[count].month,
                &LineData[count].day, &LineData[count].year, &LineData[count].hour,
                &LineData[count].minute, LineData[count].string1, &LineData[count].number,
                &LineData[count].number1, &LineData[count].string2);

This is what I'm trying to read:

12/16/2008 10:21 AM 969 bobthebuilder.html
08/14/2008 06:13 AM 10,261 purplebarney.html
08/14/2008 06:08 AM 12,083 mrpotatohead.html
08/09/2008 05:10 PM 4,076 spongebob.html
08/09/2008 05:41 PM 3,531 thewiggles.html
12/06/2008 03:04 PM 1,016 lindsaylohan.html

Output:

12/16/2008 10:21 AM 969,0
8/14/2008 6:13 AM 10,261 purplebarney.html
8/14/2008 6:8 AM 12,83 mrpotatohead.html
8/9/2008 5:10 PM 4,76 spongebob.html
8/9/2008 5:41 PM 3,531 thewiggles.html
12/6/2008 3:4 PM 1,16 lindsaylohan.html

1. The first line is still wrong.

2. And notice the 0 missing from line 3 & 4? What do you suppose is going on there?

I am guessing the program thinks the comma in the numbers is actually a string.

I had previously tried to exclude the comma with:

Code:

sscanf(LineData[count].stringstorage, "%d%/%d/%d %d:%d %s %[^,]d %s", &LineData[count].month,
            &LineData[count].day, &LineData[count].year, &LineData[count].hour,
            &LineData[count].minute, LineData[count].string1, &LineData[count].number,
            &LineData[count].number1, &LineData[count].string2);

But that resulted in partial garbage output.

Time to go to sleep! Goodnight! ZZZzzzzzzzzz.....

**happyclown** · 01-23-2009

Well, I still can't get this program to work.

Here's my code. Please ignore the block of comments in the middle. That's just for my own use.

Code:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define NUMBEROFFILES 1500
#define LINELENGTH 150
#define FILENAMELENGTH 40
#define BEGINNINGOFHTMLLIST 5  /* First file in html list */

int main( void )
{ 
    int lastfilenumber;
    FILE *openfile, *comma;
    int counter;

	struct data {
        int month, day, year, hour, minute;
        char string1[2+1];
		int number1, number2;
        char string2[FILENAMELENGTH];
        char stringstorage[LINELENGTH];  /* Used to store strings from file */
    } LineData[NUMBEROFFILES];

    /* Get a list of files in the directory "testwebsite", and redirect the
    output to a file called "directorylisting.txt". */

    // system("dir c:\\testwebsite\\*.html > directorylisting.txt");

    /* Test to see that the file "directorylisting.txt" can be opened for reading. */

    if( (openfile = fopen("directorylisting1.txt", "rt")) == NULL)
    {
        perror("\ndirectorylisting1.txt");
        exit( EXIT_FAILURE );
    }

    /* Copy the lines in the file to the array */

    counter = 0;

    while((fgets(LineData[counter].stringstorage, LINELENGTH, openfile) != NULL) && (counter < NUMBEROFFILES))
    {
		lastfilenumber = counter;
        counter++;
		
    }

    fclose(openfile);

	for( counter = 0; counter < lastfilenumber; counter++)
	{
		if( (comma = strchr( LineData[counter].stringstorage, ',')) != NULL )
		{
	sscanf(LineData[counter].stringstorage, "%d%/%d/%d %d:%d %s %d,%d %s",&LineData[counter].month, 
&LineData[counter].day, &LineData[counter].year, 
&LineData[counter].hour,&LineData[counter].minute,LineData[counter].string1,
&LineData[counter].number1,&LineData[counter].number2, &LineData[counter].string2);
		}

		if( (comma = strchr( LineData[counter].stringstorage, ',')) == NULL )
		{
sscanf(LineData[counter].stringstorage, "%d%/%d/%d %d:%d %s %d,%d %s", &LineData[counter].month, 
&LineData[counter].day, &LineData[counter].year, &LineData[counter].hour, &LineData[counter].minute,
LineData[counter].string1, &LineData[counter].number1, &LineData[counter].string2);
		}

		for( counter = 0; counter < lastfilenumber; counter++) 
		{
			printf("Filename #%d: %s", counter, LineData[counter].string2);
		}
	}

    return 0;
}

My aim is to read a file containing:

Code:

12/16/2008  10:21 AM               969 bobthebuilder.html
08/14/2008  06:13 AM            10,261 purplebarney.html
08/14/2008  06:08 AM            12,083 mrpotatohead.html
08/09/2008  05:10 PM             4,076 spongebob.html
08/09/2008  05:41 PM             3,531 thewiggles.html
12/06/2008  03:04 PM             1,016 lindsaylohan.html

And to print out a list of filenames ending in .html only(LineData[counter].string2). I don't want to print out anything else in the line.

Here is the output:

Filename #0: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ12/16/2008 10:21 AM 969 bobthebuilder.html
Filename #1: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/14/2008 06:13 AM 10,261 purplebarney.html
Filename #2: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/14/2008 06:08 AM 12,083 mrpotatohead.html
Filename #3: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/09/2008 05:10 PM 4,076 spongebob.html
Filename #4: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/09/2008 05:41 PM 3,531 thewiggles.html
Filename #5: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ12/06/2008 03:04 PM 1,016 lindsaylohan.html

Why is it printing out the entire line, as well as some garbage?

Thanks.

**happyclown** · 01-23-2009

Actually, I made a mistake in the loop for the situation if a string does not contain a comma. This is the corrected code:

Code:

if( (comma = strchr( LineData[counter].stringstorage, ',')) == NULL )
		{
	sscanf(LineData[counter].stringstorage, "%d%/%d/%d %d:%d %s %d %s", &LineData[counter].month,
&LineData[counter].day,&LineData[counter].year,&LineData[counter].hour, &LineData[counter].minute,
LineData[counter].string1,&LineData[counter].number1,
&LineData[counter].string2);
		}

And the output is now:

Filename #0: bobthebuilder.html
Filename #1: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/14/2008 06:13 AM 10,261 purplebarney.html

Filename #2: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/14/2008 06:08 AM 12,083 mrpotatohead.html

Filename #3: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/09/2008 05:10 PM 4,076 spongebob.html

Filename #4: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ08/09/2008 05:41 PM 3,531 thewiggles.html

Filename #5: ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ12/06/2008 03:04 PM 1,016 lindsaylohan.html

At least the first line works.

**happyclown** · 01-23-2009

Ok, I fixed it. The problem was that my I had the for loop to print the filenames within the for loop that used sscanf to break up the string.

Here's the working code:

Code:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define NUMBEROFFILES 1500
#define LINELENGTH 150
#define FILENAMELENGTH 40
#define BEGINNINGOFHTMLLIST 5  /* First file in html list */

int main( void )
{ 
    int lastfilenumber;
    FILE *openfile, *comma;
    int counter;

	struct data {
        int month, day, year, hour, minute;
        char string1[2+1];
		int number1, number2;
        char string2[FILENAMELENGTH];
        char stringstorage[LINELENGTH];  /* Used to store strings from file */
    } LineData[NUMBEROFFILES];

    /* Get a list of files in the directory "testwebsite", and redirect the
    output to a file called "directorylisting.txt". */

    // system("dir c:\\testwebsite\\*.html > directorylisting.txt");

    /* Test to see that the file "directorylisting.txt" can be opened for reading. */

    if( (openfile = fopen("directorylisting1.txt", "rt")) == NULL)
    {
        perror("\ndirectorylisting1.txt");
        exit( EXIT_FAILURE );
    }

    /* Copy the lines in the file to the array */

    counter = 0;

    while((fgets(LineData[counter].stringstorage, LINELENGTH, openfile) != NULL) && (counter < NUMBEROFFILES))
    {
		lastfilenumber = counter;
        counter++;
		
    }

    fclose(openfile);

	for( counter = 0; counter < lastfilenumber; counter++)
	{
		if( (comma = strchr( LineData[counter].stringstorage, ',')) != NULL )
		{		
sscanf(LineData[counter].stringstorage, "%d%/%d/%d %d:%d %s %d,%d %s", &LineData[counter].month,
&LineData[counter].day, &LineData[counter].year, &LineData[counter].hour,
&LineData[counter].minute, LineData[counter].string1, &LineData[counter].number1,
&LineData[counter].number2, &LineData[counter].string2);
		}

		if( (comma = strchr( LineData[counter].stringstorage, ',')) == NULL )
		{
	sscanf(LineData[counter].stringstorage, "%d%/%d/%d %d:%d %s %d %s", &LineData[counter].month,
&LineData[counter].day, &LineData[counter].year, &LineData[counter].hour, &LineData[counter].minute,
LineData[counter].string1, &LineData[counter].number1,&LineData[counter].string2);
		}
	}

	for( counter = 0; counter < lastfilenumber; counter++) 
	{	
			printf("Filename #%d: %s\n", counter, LineData[counter].string2);
	}

    return 0;
}

Here's the output:

Filename #0: bobthebuilder.html
Filename #1: purplebarney.html
Filename #2: mrpotatohead.html
Filename #3: spongebob.html
Filename #4: thewiggles.html
Filename #5: lindsaylohan.html

MISSION ACCOMPLISHED!

C is AWESOME!

**Elysia** · 01-23-2009

If C is awesome, you should try C++

It even more awesome, with things that will amaze you to your core

But on a serious note, your indentation needs work.

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