我无法在VS2019中使用“ fscanf”

Question

hello

我在DEVC ++中使用了“ fscanf（f，”％d“，＆a）”，它仍然有效。但是我在VS2019中写了“ fscanf”和错误。

Answer 1

不要使用fscanf，这是不安全的，不再应该使用，请使用fscanf_s。 C是一门古老的语言，因此它有很多不应该使用且不能删除的东西。

https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/fscanf-s-fscanf-s-l-fwscanf-s-fwscanf-s-l?view=vs-2017

// crt_fscanf_s.c
// This program writes formatted
// data to a file. It then uses fscanf to
// read the various data back from the file.

#include <stdio.h>
#include <stdlib.h>

FILE *stream;

int main( void )
{
   long l;
   float fp;
   char s[81];
   char c;

   errno_t err = fopen_s( &stream, "fscanf.out", "w+" );
   if( err )
      printf_s( "The file fscanf.out was not opened\n" );
   else
   {
      fprintf_s( stream, "%s %ld %f%c", "a-string",
               65000, 3.14159, 'x' );
      // Set pointer to beginning of file:
      fseek( stream, 0L, SEEK_SET );

      // Read data back from file:
      fscanf_s( stream, "%s", s, _countof(s) );
      fscanf_s( stream, "%ld", &l );

      fscanf_s( stream, "%f", &fp );
      fscanf_s( stream, "%c", &c, 1 );

      // Output data read:
      printf( "%s\n", s );
      printf( "%ld\n", l );
      printf( "%f\n", fp );
      printf( "%c\n", c );

      fclose( stream );
   }
}