Thread: Reading a text file

Originally Posted by andrew89

I'm confused... why make a link to open the same thread? Same URL and everything. I'm very confused.

Just demonstrating recursion

The other thread is here.

Alright, I'm giving this a check, I'll post any updates soon.
Thanks Jim.

Dean.

Originally Posted by jimblumberg

You need to check your compiler settings and insure that warnings are being emitted, and that they are set to as high as possible. Here are the warnings I got when I compiled your code:


Also please stop trying to put so much on one line, it makes your code harder to read, troubleshoot, and repair.

Instead of:

Code:

while((fgets(buffer,1024, fp) != NULL)) {sscanf(buffer,"%s %d %s",Tipo,&vertice,&condicao); vertice==vertice1;}

In my opinion the following is much easier to read:

Code:

while((fgets(buffer,1024, fp) != NULL)) 
{
   sscanf(buffer,"%s %d %s",Tipo,&vertice,&condicao); 
   vertice==vertice1;
}

By seperating the code onto several lines then your error/warning messages would be easier to figure out.

Code:

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

void ver()
{
   char buffer[1024];
   FILE *fp;
   fp = fopen("lol.txt","r");
   char Tipo[10];
   char condicao[20];
   int total_vertice;
   int vertice;
   int vertice1;
   int vertice2;
   int v_origem;
   int v_destino;
   fscanf(fp,"%s %d",Tipo,&total_vertice);
   printf("Neste grafo há um total de %d vertices.\n",total_vertice);
   while((fgets(buffer,1024, fp) != NULL))
   {
      sscanf(buffer,"%s %d %s",Tipo,&vertice,&condicao);
      vertice==vertice1;
   }
   printf("%d",vertice1);
   while((fgets(buffer,1024, fp) != NULL))
   {
      sscanf(buffer,"EDGE %d %d",Tipo,&v_origem,&v_destino);
      v_origem==vertice2;
   }
   if(vertice1==vertice2) {
      printf("O vértice %d tem a condicao '%s' e o seu sucessor é o %d",&vertice1,&condicao,&v_destino);
   }
   else printf("ola \n");
}




int main ()
{
   ver();
}

The error messages become:


You do not need the two while() loops, the only way you get out of the loop is if fgets() fails to read any information, which is usually at the end of file. So you should try to read all the information in your file in one loop. Read one line into your buffer, then check to see where you are in your file, does the buffer contain, the word GRAPH, NODE, or EDGE? To test which of these words is in your string, use sscanf() to retrieve one string from the beginning of your string. Then use strcmp() to test the value. Then once you figure out what type of data you are dealing with you will need to read the data into the correct variables.


Jim

Jim, let me try to understand what you're saying.

Using :

Code:

while((fgets(buffer,1024, fp) != NULL))

I'm getting every each line that is different from NULL. I'm guessing in each line I should be doing an sscanf to retrieve one string from the beggining.
Thing is, doesn't sscanf have to follow a strict modul, like if I'm using :

Code:

sscanf(buffer,"%s %d %d",Tipo,&v_origem,&v_destino);

It will only scan the lines that start by a %s and then gets followed by two %d's, right ?
So, I'm guessing I should be doing this :

Code:

sscanf(buffer,"%s",Tipo);

And this Tipo would retrieve me either EDGE, NODE or GRAPH, correct ?
Thanks, Dean.

Originally Posted by DeanWinchester

Jim, let me try to understand what you're saying.
So, I'm guessing I should be doing this :

Code:

sscanf(buffer,"%s",Tipo);

And this Tipo would retrieve me either EDGE, NODE or GRAPH, correct ?
Thanks, Dean.

That sounds correct, You may want to try it, after the scanf print out the value.

Code:

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
 
void ver()
{
   char buffer[1024];
   FILE *fp;
   fp = fopen("lol.txt","r");
   char Tipo[10];
   char condicao[20];
   int total_vertice;
   int vertice;
   int vertice1;
   int vertice2;
   int v_origem;
   int v_destino;
   fscanf(fp,"%s %d",Tipo,&total_vertice);
   printf("Neste grafo há um total de %d vertices.\n",total_vertice);
   while((fgets(buffer,1024, fp) != NULL))
   {
      sscanf(buffer,"%s",Tipo);

      printf("BUFFER: \n%s\nTipo: %s\n", buffer, Tipo);
   }

.....

That worked just perfectly except for the first line, it prints it out twice

Check it out Jim.

Code:

Neste grafo há um total de 18 vertices.BUFFER: 
                                             
nTipo: GRAPH
BUFFER: 


nTipo: GRAPH
BUFFER: 
NODE 1 if x0 < 0                                                     
nTipo: NODE
BUFFER: 
NODE 2 := x1 -x0                                                     
nTipo: NODE
BUFFER: 
NODE 3 := x2 x1                                                     
nTipo: NODE
BUFFER: 
NODE 4 := y3 y0                                                     
nTipo: NODE
BUFFER: 
NODE 5 if y0 < 0                                                                                                      
nTipo: NODE
BUFFER: 
  
nTipo: NODE
BUFFER: 
EDGE 1 2                                                     
nTipo: EDGE
BUFFER: 
EDGE 2 3                                                     
nTipo: EDGE
BUFFER: 
EDGE 3 4                                                     
nTipo: EDGE
BUFFER: 
EDGE 4 2                                                    
nTipo: EDGE
BUFFER: 
EDGE 1 5
nTipo: EDGE

But as for the rest, it's looking good.
Thanks, Dean.

Try getting rid of the fscanf() that is before the loop.

Jim

Code:

BUFFER: 
GRAPH 18                                             
nTipo: GRAPH
BUFFER: 


nTipo: GRAPH

I don't understand why the type is GRAPH when the BUFFER has nothing in it

Post your current code.

Jim

Code:

void ver()
{
   char buffer[1024];
   FILE *fp;
   fp = fopen("lol.txt","r");
   char Tipo[10];
   char condicao[20];
   int total_vertice;
   int vertice;
   int vertice1;
   int vertice2;
   int v_origem;
   int v_destino;
   while((fgets(buffer,1024, fp) != NULL))
   {
      sscanf(buffer,"%s",Tipo);
 
      printf("BUFFER: \n%snTipo: %s\n", buffer, Tipo);
   }
}

Dean.

Why do you get these two :

Code:

BUFFER: 
Tipo: NODE
BUFFER: 
Tipo: NODE

Also, how does your .txt look like inside ?

I'm still getting those two graphs

Thanks, Dean.

My input file contains:

GRAPH 18
NODE 1 if x0 < 0
NODE 2 := x1 -x0
NODE 3 := x2 x1
NODE 4 := y3 y0
NODE 5 if y0 < 0


EDGE 1 2
EDGE 2 3
EDGE 3 4
EDGE 4 12
EDGE 1 5
EDGE 0 0

I edited my last post explaining the "blank" lines.

To fix that I added this if statement:

Code:

      if(strlen(buffer) > 3)
      {
         sscanf(buffer,"%s",Tipo);

         printf("BUFFER: %sTipo: %s\n\n", buffer, Tipo);
      }

The reason I used 3 is because these "blank" lines have the following characters, 0x20, 0x20,0x0A (space, space, line feed).

Jim

Hmm, wasn't aware of this.
Any blank line has the characters, 0x20, 0x20 , 0x0A ?
Or only the blank likes on this file.

I'm gonna have to explain this project to my professor so I gotta know everything that I'm coding

I wrote it with the strlen(buffer) > 3 and I'm getting it perfect now

Thanks, Dean.

The spaces would only be in this file. The line feed is normal. Also be aware that several of your lines have non-printing characters, probably spaces, after the text that you see. I get the following line lengths:

Buffer: GRAPH 18
LENGTH: 9
Buffer: NODE 1 if x0 < 0
LENGTH: 69
Buffer: NODE 2 := x1 -x0
LENGTH: 69
Buffer: NODE 3 := x2 x1
LENGTH: 68
Buffer: NODE 4 := y3 y0
LENGTH: 68
Buffer: NODE 5 if y0 < 0
LENGTH: 118
Buffer:
LENGTH: 3
Buffer:
LENGTH: 3
Buffer: EDGE 1 2
LENGTH: 61
Buffer: EDGE 2 3
LENGTH: 61
Buffer: EDGE 3 4
LENGTH: 61
Buffer: EDGE 4 12
LENGTH: 62
Buffer: EDGE 1 5
LENGTH: 9
Buffer: EDGE 0 0 LENGTH: 8

Jim

Originally Posted by jimblumberg

The spaces would only be in this file. The line feed is normal. Also be aware that several of your lines have non-printing characters, probably spaces, after the text that you see. I get the following line lengths:


Jim

Why does every of those blank lines have two spaces ?
Why don't they have four, five ...
And why the \n ?

Just trying to understand why blank likes in which I didn't give any space has two spaces ...
The \n would be from the ENTER I did on that line ?