Ad:

C Discussion Thread
Unsolved
Views: 2434

Mar 17th, 2005

arrays

Expand Post »

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...

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

Similar Threads

(reformatted) How to return Multi-Dimensional Arrays in C++
What relation does **indirection operator have with Multidimensional Arrays in C++
Arrays in C++
How to Return Multidimensional Arrays in C++
C file input/output 2D arrays. in C

dello

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

31 posts
since Dec 2004

Permalink

Mar 17th, 2005

Re: arrays

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

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 );
}

Narue

Administrator

Reputation Points: 6442

Solved Threads: 1393

Bad Cop

Offline

11,807 posts
since Sep 2004

Permalink

Mar 17th, 2005

Re: arrays

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

(Toggle Plain Text)

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

(Toggle Plain Text)

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

Tight_Coder_Ex

Reputation Points: 47

Solved Threads: 17

Posting Whiz in Training

Offline

215 posts
since Feb 2005

Permalink

Mar 17th, 2005

Re: arrays

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

dello

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

31 posts
since Dec 2004

Permalink

Mar 17th, 2005

Re: arrays

>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.

Narue

Administrator

Reputation Points: 6442

Solved Threads: 1393

Bad Cop

Offline

11,807 posts
since Sep 2004

Permalink

Mar 17th, 2005

Re: arrays

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

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();
}

dello

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

31 posts
since Dec 2004

Permalink

Mar 17th, 2005

Re: arrays

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

dello

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

31 posts
since Dec 2004

Permalink

Mar 17th, 2005

Re: arrays

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.

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!

Dave Sinkula

Team Colleague

Reputation Points: 2780

Solved Threads: 312

long time no c

Offline

4,790 posts
since Apr 2004

Permalink

Mar 17th, 2005

Re: arrays

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:

C Syntax (Toggle Plain Text)

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:

C Syntax (Toggle Plain Text)

for each line
  read the name
  read 144 floats

Notice the difference?

Narue

Administrator

Reputation Points: 6442

Solved Threads: 1393

Bad Cop

Offline

11,807 posts
since Sep 2004

Permalink

Mar 17th, 2005

Re: arrays

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

dello

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

31 posts
since Dec 2004

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in C Forum Timeline: Continued Tic Tac Toe help

Next Thread in C Forum Timeline: Listing Integers in Numerical Order

DaniWeb Message

Cancel Changes

User Name
Password