c - 文件段错误(核心转储)(C-linux)

Question

当我尝试运行此程序时，出现段错误(核心转储)。它编译完美，但我收到错误，我不知道为什么。文件写入肯定有问题，因为没有这个问题就可以正常工作。任何帮助都会很棒。谢谢!

#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <crypt.h>
#include <string.h>

int
main(void)
{

FILE *f=fopen("shadow1.txt","w");


  if (f=NULL)
  {
    printf("ERROR");

  }


  unsigned long seed[2];
  char salt[] = "$1$........";
  const char *const seedchars =
    "./0123456789ABCDEFGHIJKLMNOPQRST"
    "UVWXYZabcdefghijklmnopqrstuvwxyz";
  char *password;
  int i;

  /* Generate a (not very) random seed.
     You should do it better than this... */
  seed[0] = time(NULL);
  seed[1] = getpid() ^ (seed[0] >> 14 & 0x30000);

  /* Turn it into printable characters from ‘seedchars’. */
  for (i = 0; i < 8; i++)
    salt[3+i] = seedchars[(seed[i/5] >> (i%5)*6) & 0x3f];

  /* Read in the user’s password and encrypt it. */
  password = crypt(getpass("Password:"), salt);

  /* Print the results. */
  //fprintf(f,"%s $ %s",password);
  printf("Success Registration to file !");
  fclose(f);
  return 0;

}

Answer 1

 if (f=NULL)
  {
    printf("ERROR");

  }

问题是...