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Join Date: Dec 2004

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dello

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arrays

Mar 17th, 2005

hi, wonder if anyone can help me.

I have a text file with the following format:

town_name followed by 12 real numbers i.e

London 7.24 8.15 6.45 3.24 3.66 2.45 4.71 6.78 6.45 8.61 7.45 6.55
Manchester 12.23 10.67 7.56 4.34 5.55 6.29 8.77 14.77 9.77 7.49 8.34 7.66
Liverpool 10.12 6.76 7.87 6.66 4.56 7.82 12.63 9.62 6.02 7.94 8.34 9.18
Bristol 6.55 8.61 4.67 4.86 5.55 2.39 6.66 4.91 2.93 4.66 4.81 7.39
ZZZZZ

the ZZZZZ is a sentinel value which tells my program to stop reading from the file. I need to read the data file and display it in the console window. However I can only get it to work when I have only one number next to the town name, as soon as the others go in, i get strange results. the entire data set needs to be held in an array as I need to do calculations to the data, below is the code I have developed so far...

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <string.h>
 
const int maxrows=12;
const int maxcols=12;
const int maxchar=10;
 
static char place[maxrows][maxchar];
static char dummy[maxchar];
float rain[maxrows];
float average, annual, wet, dry; 
 
FILE *fp;
 
main ()
{
    int i=0;
    if ((fp = fopen("data1.txt", "r"))==NULL)
       printf("Error opening file\n");
    else
    {
        do
        {
            printf("\n");
            fscanf(fp,"%s",&dummy);
            if (strcmp(dummy, "ZZZZZ") !=0)
            {
                strcpy(place[i],dummy);
                fscanf(fp,"%f",&rain[i]);
                printf("%10s\t%2.2f", place[i],rain[i]);
                i++;
            }
        } while ((strcmp(dummy,"ZZZZZ") !=0) and (i<maxrows));
    }
    fclose(fp);
    getchar();
}
#include <stdio.h>
#include <string.h>

const int maxrows=12;
const int maxcols=12;
const int maxchar=10;

static char place[maxrows][maxchar];
static char dummy[maxchar];
float rain[maxrows];
float average, annual, wet, dry; 

FILE *fp;

main ()
{
    int i=0;
    if ((fp = fopen("data1.txt", "r"))==NULL)
       printf("Error opening file\n");
    else
    {
        do
        {
            printf("\n");
            fscanf(fp,"%s",&dummy);
            if (strcmp(dummy, "ZZZZZ") !=0)
            {
                strcpy(place[i],dummy);
                fscanf(fp,"%f",&rain[i]);
                printf("%10s\t%2.2f", place[i],rain[i]);
                i++;
            }
        } while ((strcmp(dummy,"ZZZZZ") !=0) and (i<maxrows));
    }
    fclose(fp);
    getchar();
}

thanks in advance

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Join Date: Sep 2004

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Narue

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Re: arrays

Mar 17th, 2005

Think in terms of rows of records consisting of fields instead of rows and columns:

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 C Syntax (Toggle Plain Text) 
in = fopen ( "data1.txt", "r" );
if ( in == NULL ) {
  /* Error */
} else {
  int i, j;
 
  do {
    fscanf ( in, "%s", dummy );
    if ( strcmp ( dummy, "ZZZZZ" ) == 0 )
      break;
 
    /* Fill the ith record */
    strcpy ( place[i], dummy );
    for ( j = 0; j < max_cols; j++ )
      fscanf ( in, "%f", &rain[i] );
 
    /* Display the ith record */
    printf ( "%10s\t", place[i] );
    for ( j = 0; j < max_cols; j++ )
      printf ( "%2.2f", rain[i] );
    printf ( "\n" );
  } while ( i < max_rows );
}
in = fopen ( "data1.txt", "r" );
if ( in == NULL ) {
  /* Error */
} else {
  int i, j;

  do {
    fscanf ( in, "%s", dummy );
    if ( strcmp ( dummy, "ZZZZZ" ) == 0 )
      break;

    /* Fill the ith record */
    strcpy ( place[i], dummy );
    for ( j = 0; j < max_cols; j++ )
      fscanf ( in, "%f", &rain[i] );

    /* Display the ith record */
    printf ( "%10s\t", place[i] );
    for ( j = 0; j < max_cols; j++ )
      printf ( "%2.2f", rain[i] );
    printf ( "\n" );
  } while ( i < max_rows );
}

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Join Date: Feb 2005

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Tight_Coder_Ex Tight_Coder_Ex is offline

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Re: arrays

Mar 17th, 2005

First thing I saw was you mixed a little basic with C.

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while ((strcmp(dummy,"ZZZZZ") !=0) && (i<maxrows));

not and. Other than that you were so close. All you needed to do was make another loop inside your do loop

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strcpy(place[i],dummy);
 
	for (int x = 0; x < 12; x++) {
		fscanf(fp,"%f",&rain[x]);
		printf("\n\t%10s\t%2.2f", place[i],rain[x]); }
	i++;

and that solved the problem. I also cleaned up the display a little with the carriage return / tab.

Didn't mean to discredit your response Narue, but it didn't show up until I hit submit.

Last edited by Tight_Coder_Ex; Mar 17th, 2005 at 11:38 am. Reason: Narue's response

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Join Date: Dec 2004

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dello

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Re: arrays

Mar 17th, 2005

thanks for your response guys,

I had actually just about figured it out before I read the resonses but they were really helpful, just pushed me in the right direction!

thanks again guys

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Join Date: Sep 2004

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Narue

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Re: arrays

Mar 17th, 2005

>First thing I saw was you mixed a little basic with C.
You're gonna love this.

In C, since the 95 ammendment, the header <iso646.h> defines macros such as and, or, and not_eq as a reasonable alternative to the nasty trigraphs for implementations that don't support the requisite characters to represent the base language. In standard C++ all of those macros are language keywords. So it's not quite a stretch to imagine C or C++ code using them.

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Join Date: Dec 2004

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dello

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Re: arrays

Mar 17th, 2005

can someone have a look at this for me please? i cannot understand why i am getting all the spare 0.00 numbers when i compile!

a text file is required as before, the details are in my first post in this thread

thanks

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <string.h>
 
const int maxrows=12;
const int maxcols=12;
const int maxchar=10;
 
static char place[maxrows][maxchar];
static char dummy[maxchar];
float rain[maxrows][maxcols];
float average, annual, wet, dry; 
 
FILE *fp;
 
main ()
{
    int x=0;
    if ((fp = fopen("data1.txt", "r"))==NULL)
       printf("Error opening file\n");
    else
    {
        do
        {
            printf("\n\n");
            fscanf(fp,"%s",&dummy);
            if (strcmp(dummy, "ZZZZZ") !=0)
            {
                strcpy(place[x],dummy);
                printf("%10s", place[x]);
                annual=0;
                for (int i=0; i<maxrows; i++) 
                {
                    for(int j=0; j<maxcols; j++)
                    {
                        fscanf(fp,"%f",&rain[i][j]);
	                    printf("\t%2.2f",rain[i][j]); 
	                    annual=annual+rain[i][j];
                    }    
	             }printf("\tAnnual rainfall is %3.2f", annual);
	             x++;
            }
        } while ((strcmp(dummy,"ZZZZZ") !=0) && (x<maxrows));
    }
    fclose(fp);
    getchar();
}
#include <stdio.h>
#include <string.h>

const int maxrows=12;
const int maxcols=12;
const int maxchar=10;

static char place[maxrows][maxchar];
static char dummy[maxchar];
float rain[maxrows][maxcols];
float average, annual, wet, dry; 

FILE *fp;

main ()
{
    int x=0;
    if ((fp = fopen("data1.txt", "r"))==NULL)
       printf("Error opening file\n");
    else
    {
        do
        {
            printf("\n\n");
            fscanf(fp,"%s",&dummy);
            if (strcmp(dummy, "ZZZZZ") !=0)
            {
                strcpy(place[x],dummy);
                printf("%10s", place[x]);
                annual=0;
                for (int i=0; i<maxrows; i++) 
                {
                    for(int j=0; j<maxcols; j++)
                    {
                        fscanf(fp,"%f",&rain[i][j]);
	                    printf("\t%2.2f",rain[i][j]); 
	                    annual=annual+rain[i][j];
                    }    
	             }printf("\tAnnual rainfall is %3.2f", annual);
	             x++;
            }
        } while ((strcmp(dummy,"ZZZZZ") !=0) && (x<maxrows));
    }
    fclose(fp);
    getchar();
}

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Join Date: Dec 2004

Posts: 26

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dello

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Re: arrays

Mar 17th, 2005

never mind, its sussed now, was a simple error on my part!!

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Join Date: Apr 2004

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Dave Sinkula Dave Sinkula is offline

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long time no c

Re: arrays

Mar 17th, 2005

Your nested for loops mean that you are trying to read 144 values each line. To me it looks like the do...while is attempting to be what the first for loop should be: rows. I'd do something more like this.

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
      for ( int i = 0; i < maxrows; ++i )
      {
         fscanf ( fp,"%s", place[i] );
         if ( strcmp ( place[i], "ZZZZZ" ) == 0 )
         {
            break;
         }
         printf ( "%10s", place[i] );
 
         annual = 0;
         for ( int j = 0; j < maxcols; ++j )
         {
            fscanf ( fp, "%f", &rain[i][j] );
            printf ( "\t%2.2f", rain[i][j] );
            annual = annual + rain[i][j];
         }
         printf("\tAnnual rainfall is %3.2f\n", annual);
      }
      for ( int i = 0; i < maxrows; ++i )
      {
         fscanf ( fp,"%s", place[i] );
         if ( strcmp ( place[i], "ZZZZZ" ) == 0 )
         {
            break;
         }
         printf ( "%10s", place[i] );

         annual = 0;
         for ( int j = 0; j < maxcols; ++j )
         {
            fscanf ( fp, "%f", &rain[i][j] );
            printf ( "\t%2.2f", rain[i][j] );
            annual = annual + rain[i][j];
         }
         printf("\tAnnual rainfall is %3.2f\n", annual);
      }

Last edited by Dave Sinkula; Mar 17th, 2005 at 6:02 pm. Reason: :o Can't count!

"One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary." --Ayn Rand

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Join Date: Sep 2004

Posts: 7,847

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Narue

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Senior Bitch

Re: arrays

Mar 17th, 2005

Unless the format of your file has changed, you're trying to read too many floats, and fscanf is failing miserably when you get to the next city. Here's how any logic you use should work:

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for each line
  read the name
  read 12 floats

Anything else will give you incorrect output. As it is, your code is trying to do this:

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C Syntax (Toggle Plain Text)

for each line
  read the name
  read 144 floats

Notice the difference?

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Join Date: Dec 2004

Posts: 26

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dello

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Re: arrays

#10

Mar 17th, 2005

yes, i figured it out now, i realised that it was trying to read in far too many values but it is working fine now..

thanks again

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