line reading problem

[papous]

i am trying to wtite a small program which reads a file and writes out the nmber of lines in that file.i wrote a function which reads one line which works fine.my problem is how to make this program to read big files while i dont know the number of lines.please help

[Devil Panther]

try this:

#define MAX 150
#define file "cool.txt"
FILE *fp;
char line[MAX]={0};
int num=0;

fp = fopen(file, "rb");
while (fgets(line, MAX, fp)!=NULL)
 num++;
fclose(fp);
printf("%s has %d number of lines.", file, num);

[Gades]

Hi, I'm a newbie, but I use this:

int count_lines ( ) {

   char buff[BUFSIZ];
   int contador = 0;
   char  file_name[PATH_MAX];
   FILE *input;

   strcpy (file_name, material);
   input = fopen(file_name, "r");
   while ( fgets( buff, BUFSIZ, input ) != NULL ) {
         contador++;
   }
   fclose( input );
   return (contador);

}

[papous]

here is the code,but is still not working fine:

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

typedef char * STRNG;
STRNG code[80];
STRNG get_line(FILE * inf)
{
STRNG s;
char tok = getc(inf);
int count = 0;
s = malloc(80);
while(tok!='\n')
{
s[count++] = tok;
tok = getc(inf);
}
s[count] = '\0';
return s;
}

int main(int argc, char *argv[])
{
char* filename;
FILE *stream;
filename =argv[1];
int n=0;

stream=fopen(filename,"r");
if(stream ==NULL)
{ printf("Enter a valid parameter.Program will exit.\n");
exit(1);
}

code[n]=get_line(stream);
while(code[n]!=NULL){
n++;
}
printf("%d\n",n);
return 1;
}

this program reading the file below is suppose to read 11 lines:

line1
line2

line4: follows a blank line
line5
line6: This contains the words cat and dog.

line8: follows a blank line

line10: This also contains cat, dog, and rabbit.
line11: One more containing the word cat.

[papous]

here is the code,but is still not working fine:

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

typedef char * STRNG;
STRNG code[80];
STRNG get_line(FILE * inf)
{
STRNG s;
char tok = getc(inf);
int count = 0;
s = malloc(80);
while(tok!='\n')
{
s[count++] = tok;
tok = getc(inf);
}
s[count] = '\0';
return s;
}

int main(int argc, char *argv[])
{
char* filename;
FILE *stream;
filename =argv[1];
int n=0;

stream=fopen(filename,"r");
if(stream ==NULL)
{ printf("Enter a valid parameter.Program will exit.\n");
exit(1);
}

code[n]=get_line(stream);
while(code[n]!=NULL){
n++;
}
printf("%d\n",n);
return 1;
}

this program reading the file below is suppose to read 11 lines:

line1
line2

line4: follows a blank line
line5
line6: This contains the words cat and dog.

line8: follows a blank line

line10: This also contains cat, dog, and rabbit.
line11: One more containing the word cat.

[papous]

should i better deal with EOF instead of looking for NULL?

[foniks munkee]

I would try something like

while (!feof(stream))
{
/* Do stuff */
}

The feof macro is designed to detect EOF on a stream, very useful..

[Unregistered]

thanks foniks
the program almost works fine exept that it wont print out the final value of i.is like the printf doesnt exist.can somebody tell me why?

int main(int argc, char *argv[])
{
FILE *stream;
stream=fopen(argv[1],"r");
if(stream ==NULL){
    printf("Enter a valid parameter.Program will exit.\n");
    exit(1);
    }

while(!feof(stream)){
	code[n]=get_line(stream);
	printf("%s\n",code[n]);
	i++;

    }

printf("%d\n",i);/*Here is the problem*/

return 1;
}

thanks in advance

[Salem]

Well it breaks with a segmentation fault here.

The main problem is that feof() isn't all that it seems to be.

In order for feof() to return true, first char tok = getc(inf); must return EOF.
But as soon as it does that, it will always return EOF - which is a problem for your while loop, which only exits when it sees a \n.

The upshot of this, is that this code loops at EOF until count reaches a sufficiently large number to cause a problem.

[Devil Panther]

The fgets returns NULL and not EOF when it reaches to the end of the file, no more lines to read!

[Unregistered]

the program is supposed to read empty lines as well.i changed the code into this:

int main(int argc, char *argv[])
{

    int n=0;
	int c;
FILE *stream;
stream=fopen(argv[1],"r");
if(stream ==NULL){
    printf("Enter a valid parameter.Program will exit.\n");
    exit(1);
    }

do{
	code[n]=get_line(stream);
	printf("%s\n",code[n]);


    }while(c=fgetc(stream)!=EOF);

printf("anything");
fclose(stream);
return 0;
}

now the program terminates but it cant read the empty lines and the starting character frome some lines is missing too.i guess the problem is in the while loop which is in the get_line function.i am confused and i cant think of something else.
i guess is a challenge coze two of my tutors couldnt resolve the problem and they claim to be c experts.please help

[Salem]

Mmmmmm

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

typedef char * STRNG;

STRNG code[80];

STRNG get_line(FILE * inf) {
    STRNG s = NULL;
    int count = 0;
    int tok;            // must be int - EOF is an int, not a char

    while ( (tok=getc(inf)) != EOF && tok != '\n' ) {
        if ( s == NULL ) s = malloc( 80 );
        s[count++] = tok;
    }
    if ( tok != EOF ) {
        if ( s == NULL ) s = malloc( 80 );  // possibly a newline on its own
        s[count++] = tok;                   // append the \n
        s[count] = '\0';
    }
    return s;
}

int main(int argc, char *argv[]) {
    char    *filename;
    FILE    *stream;
    int     i, n = 0;            // Moved C++ declaration

    filename =argv[1];
    stream=fopen(filename,"r");
    if(stream ==NULL)
    {
        printf("Enter a valid parameter.Program will exit.\n");
        exit(1);
    }

    while ( (code[n]=get_line(stream)) != NULL ) {
        n++;
    }

    printf( "%d lines found\n", n );
    for ( i = 0 ; i < n ; i++ ) {
        printf( "%02d %s", i, code[i] );
    }

    return 0;  // 0 is success
}

[papous]

thanks Salem.that was real good.