How would I go about counting the lines in a text file?

I am refreshing my C knowledge, I am wondering how I would count the number of lines in a text file?

I have looked up the ascii code for a CR, this being 0x15, is it as simple as scanning the file for CR's?

This is just a practical exercise to get back into C.

Cheers Mick

here is what I have so far...

Code:

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//name:              linecount.c
//description: counts the number of lines in a text document
//

#include <stdio.h>
#include <stdlib.h>                //need for file operations?
void main(int argc,char *argv[])
{
        int count=0,c;
        FILE *ifp,*ofp;

       
        ifp = fopen(argv[1],"r");
        while((c=getc(ifp))!=EOF)
                if(c==\r)
                        count++;
        printf("the charater count was:%5d\n",count);
}

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Ok worked the last one out, now I am trying to convert to a function, what is wrong with this?

Code:

---

//name:              linecount.c
//description: counts the number of lines in a text document
//

#include <stdio.h>
#include <stdlib.h>                //need for file operations?
void linecount(int,char);

void main(int argc,char *argv[])
{
        linecount(int argc,char *argv[]);
}               

void linecount(int argc,char *argv[])
{
        int count=0,c;       
                FILE *ifp,*ofp;       

       
                ifp = fopen(argv[1],"r");
                        while((c=getc(ifp))!=EOF)
                                if(c=='\n')
                        count++;
                printf("the number of lines is:%5d\n",count);
}

---

Cheers Mick

Why would you call it like this:

Code:

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linecount(int argc,char *argv[]);

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Shouldn't it be this?

Code:

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linecount(argc, argv);

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Shouldnt this:

Code:

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void linecount(int,char);

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Be this?

Code:

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void linecount(int, char**);

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Your compiler should probably be making these errors obvious.

Code:

---

//name:              linecount.c
//description: counts the number of lines in a text document
//

#include <stdio.h>
#include <stdlib.h>                //need for file operations?

void linecount(int, char**);

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

}               
void linecount(int, char**)


{
        int count=0,c;       
                FILE *ifp,*ofp;       

       
                ifp = fopen(argv[1],"r");
                        while((c=getc(ifp))!=EOF)
                                if(c=='\n')
                        count++;
                printf("the number of lines is:%5d\n",count);
}

---

This it? Still having trouble!!

- main return type should be int.
- main should return 0 (not required - thanks laserlight).
- linecount's implementation arguments should have names (just like main).

You could really improve your formatting. You should probably change the linecount interface, instead of taking argc/argv, extract the filename from argc/argv and pass it as a c-string to linecount.

Quote:

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Originally Posted by mickpc

This it? Still having trouble!!

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Why on Earth would you want to pass all of argc and argv to linecount, esp. since you don't use it? If you are going to write a function, make it in some sense "functional" relative to the rest of the program, eg.

Code:

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#include <stdio.h>

int linecount (char *file) {
        int ch, total = 0;
        FILE *fp = fopen(file,"r");
        if (!fp) return -1;
        while ((ch=fgetc(fp)) != EOF) if (ch==10) total++;
        fclose(fp);
        return total;
}

int main (int argc, char *argv[]) {
        int num_of_lines;
        if (argc<2) {
                puts("Filename required!");
                return 0;
        }
        num_of_lines = linecount(argv[1]);
        printf("\n%d lines in \"%s\"\n",num_of_lines,argv[1]);
        return 0;
}

---

Code:

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#include <stdio.h>

#define EOL              '\n'
#define CAR_RETURN '\r'

int line_count(char* __str_file_name) {
  FILE* fd;
 
  if ((fd = fopen(__str_file_name, "r")) == NULL) {
      printf("[Error] : While opening the file\n");
      exit;
  }

  unsigned int line_count = 0;
  while ( (ch = fgetc(fd)) != EOF)
    if (ch == EOL || ch == CAR_RETURN)
        ++line_count;

  if (fd) {
    fclose(fd);
  }

  return line_count;
}


int main(const unsigned int argc, char* argv[] ) {
  int status = 0;
 
  if (argc < 2)
    status = -1;
  else
    printf("Number of lines in file[%s] == [%d]\n", argv[1], line_count(argv[1]));

  return status;
}

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