Thread: Reading from a .txt

Hi,

Im new in C and ive got a problem here conserning this topic.
I got a a .txt file like this:

234 234
bla bla bla
bla bla bla
345436 45645
435345 34577
456575 435645
456455 45646
bla bla bla


My problem is that ive got to associate those number to a variable int so that i can use them in another function, they are coordinates of polygons.
I can open the file and read it but i can associate them to specific int variables like x1,y1,x2,y1, etc.. I understand that i need to use gets and sscanf in a while loop, but get a error saying that im associating a char to a int.

Can u help me please and send me a exemple code?
Srry if the message is confusing but i wrote it in a hurry ))

Yes, post your code and we'll tell you what's wrong with it and what needs fixed.

Ok here is the .txt which is actually a .dat file:

533 1100
#mapa portugal
inic_pol
150 842
103 1042
478 1036
442 845
fim_pol
inic_pol
15 380
150 842
407 843
401 608
81 376
fim_pol
inic_pol
81 376
364 583
328 56
95 45
fim_pol


I have to use g2 library to draw the polygons that im thinking of drawing line to line.
The code that ive written is now showing trouble compiling, in the console appears :
/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: ld returned 1 exit status

Never the less here it goes, the shock to any mediocre programer:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <g2.h>
#include <g2_PS.h>
#include <string.h>


int main(){

int x, y;
int x1, y1, x2, y2;
int i, id;
char linha[1024];
char inicio[9] = "inic_pol\n";
char fim[8] = "fim_pol\n";     
  
i = 0;
 
        FILE * fp; 

	fp = fopen("mapa1.dat" , "r");
	if (fp == NULL){
		printf ("ERRO: ficheiro inexistente\n");
		return(0);
	}
	fgets(linha,[1024],fp);

	sscanf(linha, "%d %d\n", &x, &y);
	id = g2_open_X11( x , y);
	
	if ((strncmp( linha, inicio ))== NULL){
		while((strncmp( linha, fim ) != NULL){
			sscanf(linha, "%d %d\n", &x1, &y1);
			sscanf(linha, "%d %d\n", &x2, &y2);
			g2_line(id, x1, y1, x2, y2);
		} 
			
		
			fclose(fp);
 
       }

Oh yeah! In case you didnt notice XP english is not my mother language... Sorry about that....
linha -> line
mapa->map
inicio->start
fim->end
inic_pol-> its like inicializing polygon
end_pol-> its like ending polygon
Although i dont believe the translation of the terms is relevant i might give you a help with your intuition.
Thanks for your help...

I don't think you have the g2 library installed. If you do, then you're probably not linking it correctly.

OH ! yeah i havent finished the code yet, much because i cant compile, it keeps giving me that error.
I using linux

how should i link it?
im writing: gcc -Wall -ansi -pedantic -lm -lg2 -lgd -lX11 -file.c -o file