file copy using c in debian linux

Question

can anybody show me

wat's wrong with my code .

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
main()
{
  FILE *fp1,*fp2;
  char ch,ch1;
  fp1=fopen("ma.dat","r");
  fp2=fopen("na.dat","w");
   while(!feof(fp1))
    {
      ch=fgetc(fp1);
      fprintf(fp2,"%c ",ch);
    }    
    fclose(fp1);
    fclose(fp2);

}

i 'm trying to read from a file and writing to another file. some problem exist .

thank's in advance

What is *`"some problem exist"`* ? and avoid using feof() read [`while( !feof( file ) ) is always wrong`](http://stackoverflow.com/questions/5431941/while-feof-file-is-always-wrong) — Grijesh Chauhan, Jan 25 '14 at 05:57
You should check for eof immediately after a character read. — Abhishek Bansal, Jan 25 '14 at 05:57
I'm not sure about *anybody*, but I'm fairly confident `gdb` and/or some instrumented `printf()`s would be pretty telling. You're on Debian, so `gdb` is there. — WhozCraig, Jan 25 '14 at 06:06

Elliott Frisch · Accepted Answer · 2014-01-25T23:14:02.450

1

Change your while loop -

while(1) // or TRUE or for(;;)
{
  ch=fgetc(fp1);
  // or if (fp1 == -1)
  if (feof(fp1)) { // you're printing eof to fp2... not a good idea.
    break;
  }
  fprintf(fp2, "%c", ch); // or fputc(ch, fp2); your string format included a space!
}

or the shorter (and idiomatic) -

while ((ch = fgetc(fp1)) != EOF) 
  fputc(ch. fp2);

Or your could use the linux specific,

fseek(fp1, 0L, SEEK_END);
long sz = ftell(fp1);
fseek(fp, 0L, SEEK_SET);
sendfile(fp2, fp1, 0, sz);

edited Jan 25 '14 at 23:14

answered Jan 25 '14 at 05:57

Elliott Frisch

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while(true) 'true' cause following error fcp.c: In function ‘main’: fcp.c:10: error: ‘true’ undeclared (first use in this function) fcp.c:10: error: (Each undeclared identifier is reported only once fcp.c:10: error: for each function it appears in.) – user1 Jan 25 '14 at 06:28
@user1 sorry. TRUE or 1. – Elliott Frisch Jan 25 '14 at 06:29
while(1) works successfully. Thankyou very much for your valuable help. – user1 Jan 25 '14 at 06:39
This code works, but the idiomatic way is **while ((ch = fgetc(fp1)) != EOF) fputc(ch. fp2);** – Thomas Padron-McCarthy Jan 25 '14 at 06:50
@ThomasPadron-McCarthy Updated. And I added the even more idiomatic (and linux specific) sendfile call. – Elliott Frisch Jan 25 '14 at 23:13

file copy using c in debian linux

1 Answers1