Problem with File I/O

[abh!shek]

This code is from a book and is supposed to open & display the contents of a file ::

#include<stdio.h>
void main()
{
FILE *fp;
char ch;
clrscr();
fp=fopen("H_World.c","r");
while(1)
{
ch=fgetc(fp);
if(ch==EOF)
	break;
printf("&#37;c",ch);
}
fclose(fp);
getch();
}

This file called H_World.C is located in C:\TC
My first question is that how does the compiler know that it has to search in C:\TC??

Now I tried to experiment something.........
**1.)I made a readme.txt file in C:\TC and in the fopen argument wrote "C:\\TC\\readme.txt"
It worked !!
**2.)Now i made a folder called NEW in C:\ and put this readme file in the NEW folder,made the argument "C:\\NEW\\readme.txt".This also worked!
**3.)I put the readme file in F:\ drive....this also worked.
**4.)Now i created a new folder in F drive ,put the file in new folder,made the necessary changes in the code but it returned a "Null Pointer Assignment"

Please explain me how does this fopen() works,where does it search for the files(The book i read says it searches for the file on the entire Hard Drive but i dont think so)and why does it give error messege in experiment no.4?

Thanks...........

[Salem]

I'm guessing your fossil compiler doesn't understand spaces in filenames, or perhaps long filenames.

Try using a compiler which is actually compatible with your OS, and not just compatible with an emulation layer provided by your OS.

Oh, and the bugs.
1. main returns int, not void
2. ch should be declared as int, not char. This is so you can compare with EOF properly.

[Elysia]

And indent that mess.
fopen searches the local directory (if no path is specified) or the path specified in the filename.
Oh yes, to add to Salem's comments, void main is undefined; read my signature for more info.

[ssharish2005]

To make it more clear, and check file location. Follow Salem's and Elysia

#include<stdio.h>

/*  Main should return a value
void main() */
int main
{
   FILE *fp;
   char ch;
   /* non standard function, dont use it
   clrscr(); */
   
   fp=fopen("H_World.c","r");
   /* Check return value of fopen */
   
   if(fp == NULL)
   {
         printf("Error: File cannot be opened\n");
         return 1;
   }
   
   while(1)
   {
       ch = fgetc(fp);
       if(ch==EOF)
          break;
       printf("&#37;c",ch);
   }
   
   fclose(fp);
   
   /* getch(); */
   getchar();
   /* Should always return a value */
   return 0;
   
}

ssharish