C - Can't remove file in a folder wirh remove() - c

Question

I'm trying to remove a file in a folder using C but it's crashing & throwing me some return value
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
{
FILE *fp1;
char str[100];
gets(str);
strcat(str,"txt");
fp1 = fopen(str,"r");
fclose(fp1);
remove(str);
return 0;
}
This is not working. I'm using windows XP SP2 (32 bit) and also tried system() command in the C program, but No help. Can anyone please help to fix this issue?

Answer 1

It is unclear why you are calling fopen, you are not reading anything from it. If you are attempting to use it as a check for the file's existence, there is no need, the return from remove will tell you whether the removal was successful.
For example, you could do something like the following:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#define EXT ".txt"
#ifndef PATH_MAX
#define PATH_MAX 4096
#endif
int main (void) {
char buf[PATH_MAX] = "";
size_t len = 0;
printf ("enter filename to delete (without .txt); ");
if (!fgets (buf, sizeof buf, stdin) || *buf == '\n') {
fprintf (stderr, "error: EOF or invalid input.\n");
return 1;
}
len = strlen (buf); /* get length */
if (buf[len - 1] == '\n') /* check trailing '\n' */
buf[--len] = 0; /* overwrite with '\0' */
else {
/* handle error, input exceeded buf size */
return 1;
}
strcat (buf, EXT);
errno = 0;
if (remove (buf) == -1)
perror ("remove failed");
else
printf ("file: '%s' successfully removed.\n", buf);
return 0;
}
Example Use/Output
$ ls -al foobar.txt
-rw-r--r-- 1 david david 0 Sep 17 06:35 foobar.txt
$ ./bin/rmfile
enter filename to delete (without .txt); foobar
file: 'foobar.txt' successfully removed.
$ ./bin/rmfile
enter filename to delete (without .txt); foobar
remove failed: No such file or directory
It works the same on Linux or DOS (you just need to define PATH_MAX on windows).
Example Use/Output on Windows
c:\Users\david\Documents\dev\src-c\tmp>cl /Wall /Ox /Febin\rmfile rmfile.c
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.30319.01 for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.
rmfile.c
Microsoft (R) Incremental Linker Version 10.00.30319.01
Copyright (C) Microsoft Corporation. All rights reserved.
/out:bin\rmfile.exe
rmfile.obj
c:\Users\david\Documents\dev\src-c\tmp>echo "test on Windoze" > foobar.txt
c:\Users\david\Documents\dev\src-c\tmp>dir foobar.txt
Volume in drive C has no label.
Volume Serial Number is 2045-D579
Directory of c:\Users\david\Documents\dev\src-c\tmp
09/17/2017 06:56 AM 20 foobar.txt
1 File(s) 20 bytes
0 Dir(s) 20,235,399,168 bytes free
c:\Users\david\Documents\dev\src-c\tmp>bin\rmfile
enter filename to delete (without .txt); foobar
file: 'foobar.txt' successfully removed.
c:\Users\david\Documents\dev\src-c\tmp>bin\rmfile
enter filename to delete (without .txt); foobar
remove failed: No such file or directory
I guess if you are on windows, you should probably define the following at the top of the file to remove the strcat warning from the compiler:
#if defined (_WIN32) || defined (_WIN64)
#define _CRT_SECURE_NO_WARNINGS
#endif