fwrite一直在失败,不知道为什么

Question

在我下面的代码中,据我所知,文件正在正确写入.当我查看文件floats.dat时,我看到了这个二进制流ÍÌL@33c@ÍÌÜ@ffFAßOeA^@^@bBf6zE33äCff<83>BÍ̦B

但是我的程序总是会触发这个if语句:

if(fread(inputFloats, sizeof(float), LENGTH, binaryFile) < LENGTH)
{
   fprintf(stderr, "Problem reading some or all data from %s\n\n", binaryFileName);
   return EXIT_FAILURE;
}

有人看到我在这里做错了吗？完整代码如下.

#include <stdlib.h>
#include <stdio.h>
#define LENGTH 10

int main(void)
{
   FILE *binaryFile, *textFile;
   char *binaryFileName = "floats.dat", *textFileName = "floats.txt";
   float floats[LENGTH] = {3.2, 3.55, 6.9, 12.4, 14.332, 56.5, 4003.4, 456.4, 65.7, 83.4};
   float inputFloats[LENGTH];
   int i;

   if((binaryFile = fopen(binaryFileName, "r+")) == NULL)
   {
      fprintf(stderr, "Problem opening %s", binaryFileName);
   }

   if(fwrite(floats, sizeof(float), LENGTH, binaryFile) < LENGTH)
   {
      fprintf(stderr, "Problem writing some or all data to %s\n", binaryFileName);
      return EXIT_FAILURE;
   }

   printf("DATA WRITTEN SUCCESSFULLY\n");

   if(fread(inputFloats, sizeof(float), LENGTH, binaryFile) < LENGTH)
   {
      fprintf(stderr, "Problem reading some or all data from %s\n\n", binaryFileName);
      return EXIT_FAILURE;
   }

   for(i = 0; i < LENGTH; i++)
   {
      printf("float[%d] = %f\n", i, floats[i]);
   }

   return EXIT_SUCCESS;
}

Answer 1

• 您不使用文本数据,因此在打开文件时应指定二进制模式.用r+b而不是r+
• 你需要fseek(binaryFile, 0, SEEK_SET)在写完后"回放"文件.rewind也可以用于这种情况 - fseek允许您将读/写指针放在任何位置.